Oh, boy... You're in for a treat this fall when the Angel reruns start up!🙂 Buffy Season 4, while admittedly not as good as Seasons 2 and 3, has some truly spectacular episodes, at least one (possibly two) of which make it into my all-time top ten favorite Buffy episodes. Buffy Season 4 is even better if it's watched along with Angel Season 1. I know 'cause I have both DVDs and had the privilege of watching the two together during the summer.
Taking into account the fact that you're a huge fan of Angel's, I think Season 1 is gonna be a blast for you. I wasn't much of a fan of his until I began watching the spin-off. To me, he's an even more interesting character when he's away from Buffy. Again, do give Angel-less Buffy a shot. It may not be as enjoyable as seasons past, but it has its own certain appeal.