Oh man, I've been asked so many times on tumblr why I like Delena more than Stelena but prefer Bangel to Spuffy...
My answer was this:
Bangel and Stelena have some shallow similarities due to the fact that TVD is such a ripoff of BtVS/AtS at times, and especially when it concerns Stefan. However, TVD writers don’t really get Angel, Buffy or Bangel.
Bangel is a dynamic relationship that teaches Buffy about moral gray areas and sacrifice. Buffy’s first contact with a good demon is Angel. She realizes that certain demons have souls and can be good. She also realizes that being with Angel is essentially a conflict between her duties and what’s practical, and what she wants. Thus, it leads to emotional maturity when she gives up Angel to save the world in Becoming, or the many times she attempts to break up with him.
Angel also helps Buffy be vulnerable and hold on to that innocent girl who wants romantic dates and happily ever afters. In return, Buffy teaches Angel to fight for redemption, for himself and for others. She shows him compassion and forgiveness. She shows him the best of humanity and inspires Angel to protect it and be a part of it.
Like I said, their relationship is dynamic because they grow as people and face different challenges.
Stelena, on the other hand, doesn’t really lead to introspection or growth. Sure, Stefan and Elena help each other many times, but they never question the practicality of being together and the reason why they break up is pretty much Damon. I find their relationship boring, stagnant and superficial. In the end, Elena moved on romantically and so did Stefan. It’s not really a love for the ages. I just don’t find it engaging or memorable, but, tbh, I don’t remember the show well enough to give you a detailed explanation.
As for Sookie with Bill or Eric, neither relationship is like Bangel. Bill rapes Sookie inside a car and only moved to town because the Queen hired him to spy on Sookie. He lied to her the whole time they were together, manipulated her a few times as well, and, like I said, raped her. Truly, this is more Spuffy than Bangel. Eric is just so much more lovable despite his early actions. He also manipulated Sookie. But, you know what? True Blood doesn't follow the same moral code that BtVS does, so that's fine. The raping though? That will never be fine to me.