I've been reading these boards for a long time and love what everyone has had to say, but decided that I would join now because this particular discussion has really peaked my interest.
I believe that without magic currently it would be very difficult for the Shanshu to happen, but not impossible. The PTB, or Senior Partners, whomever it is that is actually wanting it to happen, would be able to find a way of making it happen regardless of magic being unavailable at the moment.
Regarding which Souled Vampire deserves that Shanshu, well that is a debate that can go on forever and neither side really being happy with the conclusion. However, I believe that Angel wants it more than Spike, mainly for the reason that Spike LIKES being a vampire whereas Angel doesn't, not really anyways. Spike would not, and has even admitted it multiple times, that going back to his human strength is not preferable to him. It has already been proven that not all demons go to hell, so why would vampires not also have a shot at heaven if they've been redeemed? That would be the only reason why Spike may want to be human again, a chance to not end up in hell when he's dusted for good.
Now another thing with the Shanshu is the essence of something being redeemed right? So, is it the SOUL or the DEMON that needs redemption?
In either case, Angel/Angelus has a lot to make up for before he can even be thought of as redeemed. If anything, he was better off staying human when the Mohra Demon made him that because otherwise his chance is a very very long time in coming. Angelus has never shown he wants redemption and I hardly doubt he ever will. As we saw in S2 of BTVS with the Judge, Angelus has absolutely no humanity in him, hence why he didn't burn up when touched as well as the Judge stating that fact. Angelus will never be redeemed, he doesn't want it and will never seek it out. If it is the SOUL that needs redemption, well just the fact that Angel turned Lawson during WWII was already an issue, not to mention all the things that he's done since. Angelus started 1 apocalypse, while Angel himself has started 2 (end of ATS 5 and as Twilight). Angel allowing Darla/Dru to eat those lawyers doesn't help his case nor what he did to Drogyn. Add onto the fact that he's manipulated his team by way of memory and leaving them basically no choice at the end of ATS 5 into a suicide mission, well, his soul is very tainted. Angel is not much different from Angelus in the grand scheme of things, I don't understand why people don't see that. Angel is very manipulative, controlling, and plays mind games just like Angelus. The only thing Angel doesn't seem to do as often (at least until BTVS S8) was to out and out murder and torture on a regular basis. The Angel we see in BTVS, for the most part but especially in S1, was someone that was always cryptic and never really fought the good fight most of the time. S2 he wasn't much better. It wasn't until S3 were we saw him enter the fight and that was nearing the end of the season. Angel always wants people to see him as good and hides his mistakes and flaws as best he can. Not really much different from Angelus who thinks he has no flaws at all. Angel needs to be thought of as good or great, same as Angelus. You can't see his flaws, he doesn't like it and always tries to find excuses or reasons for why he's done what he has.
We are talking about a 240 year old vampire that fell in love with the heart of a 15 year old girl sucking on a lolly pop and a complete flake at the time. I'm sorry, but there is something very very wrong with this picture and it completely makes me sick to my stomach even thinking about it. Add to the fact that he believes that she's his SOUL MATE? I mean really. Angel is Angelus on a leash, that is all. If Angelus can't love Buffy, then I doubt at all that Angel does as much as he claims to. If one half of you can't love someone even a little bit, then the other half can't love nearly as much as they claim to. Not to mention that Angel was interested in Kate, Cordy, and Nina. Just like Buffy was interested in Riley and Spike. He is fooling himself just like she is and I doubt receiving a Shanshu would have them living happily ever after. Angel needs to be the one controlling the shots, as does Buffy, they would just never ever work out.
Now we come to Spike. Like Angel, if the Soul needs to be redeemed, well Spike has nothing to worry about. Spike's Soul is clean and has nothing to be redeemed of. The only kills he has are the ones when he was controlled by the First. It wasn't even Spike that killed those people, it was the First using Spike's body. If Spike's Soul would need to be redeemed for those acts, well Xander, Willow, Faith, and Giles also have issues then as they've also instigated kills. People tend to forget that Xander was solely responsible for the singing demon back during OMWF and those people that died were his fault and taint his Soul. People also tend to forget that he attempted to rape Buffy but let him off the hook but not soulless Spike. Interesting really, considering that Xander never forgot about what he attempted even though he told Buffy he did. Both Xander and Giles don't let Spike forget it, nor let Buffy forget that Spike attempted it, but what Xander did is all ok. Such hypocrites. Also with a Soul Spike never attempted an apocalypse, in fact he died to save the World and tried to prevent the one that Angel started at the end of ATS S5. Funny that, soulless Spike also had to prevent the one Angelus started in S2. We also have the fact that both Demon and Soul in Spike love Buffy completely and allow her her own mind. Unlike Angel/Angelus, who always needs to be in control of Buffy. Spike allows her that control and just helps her work through her problems, allows her to take the lead and has complete faith in her abilities. Without or without Soul, Spike is her willing slave and to his own detriment sometimes, allows her complete control.
Now, does Spike's Demon need redemption? I tend to think it doesn't, not anymore. Now before chip Spike's Demon helped prevent an apocalypse that Angelus was starting. People say it was for selfish reasons, but really, is his love for Dru selfish? His loving the World selfish? Really, Buffy had a duty to stop Angelus as well as Giles. Xander just wanted him dusted. None of them were doing it for the proper reasons, duty and selfishness (Xander) were their reasons. If anything, Spike was the least selfish. He LOVES the World as he stated and he loved Dru and wanted to save her. He didn't want the world to end. That isn't selfish and IMO is more admirable and noble than the others had reason for. Now what about the things he did after getting the chip? Sure he helped Adam, only marginally when you think about it. He helped the Scoobies more by giving them those disks. I mean really, Adam could have easily have gone after and gotten Buffy another way. He was way more powerful and she had no idea until those disks turned up how to defeat him. Spike also didn't have to help in the end, he could have just left them all there in the bunker and hightailed it out of town and found a demon doctor to remove the chip. What about the help with Glory and not giving up Dawn? The help after Buffy died? The help after she came back? The going to ask for his Soul in the first place? I think Spike's Demon has redeemed itself and even if it hasn't, just the fact that he would have died for any of them at anytime, including at the end of S7 regardless of his Soul or not, his Demon has been redeemed. If he hadn't had his Soul and that bauble would still have worked, he still would have done it and nobody could deny that he would. He was willing and thought he would die at the end of S5 and his love hadn't changed by the end of S7.
So, in regards to the Shanshu, I believe that Spike is more worthy, however he wouldn't consider it a reward at all. I believe that when/if Spike is dusted/dies for good, he will find himself in a heavenly reward regardless. IMO Angel/Angelus is not worthy and will take centuries (at least for Angel) to make up what he's done and Angelus will never see redemption and doesn't want it regardless.
In ending of this very long post, the one thing I will say is that I find it funny that everyone thinks Angel is so great and never sees his flaws (show wise). When Spike in ATS was out fighting under direction of what he thought to be Doyle as "helping the helpless" the AI crew called him a vigilante, but when Angel was doing it through-out his whole show he was thought of as a hero. What a double standard. Angel does it and he's a hero & champion, Spike does it and he's a vigilante. I mean really? Hypocrites, all the supposed hero's on the both shows are, IMO. I would also think that both Wesley and Giles should have been more interested in Spike's Demon wanting, fighting, and getting a Soul. I mean really, Angel's has always been forced on his Demon, Spike fought and requested it. With their council doctrined teaching they both should have been all over something like that, interesting neither really cared. They both in their own way supported a vampire that was forced a Soul and disregarded the one that actually requested it. Idiots.