The 70's band with Wetton and Bruford was my favorite for a long time, largely on the strength of Red and USA. When I dug into some of the earlier studio stuff by the same band (Starless and Bible Black, Lark's Tongues in Aspic) I found it a bit jarring. Rather different sometimes, and overall less consistent.
I always thought the early 80's band with Belew, Levin, and Bruford was incredibly consistent and amazing, but I had some trouble with it. And it's for admittedly stupid reasons reasons: It didn't sound like King Crimson to me. I grew up with King Crimson. King Crimson has one guitar: Robert Fripp. But Belew is incredible and quickly won me over. It helped that I was already familiar with him because of his work with Zappa.
I find myself reaching for the 80's stuff more than the 70's stuff nowadays. Their three-album run (Discipline, Beat, Three of a Perfect Pair) beats out the three albums by the Wetton band, though just barely. It depends on my mood, too, but the 80's stuff is more consistent to me.