I did not enjoy the Seinfeld finale at all.
The finale of Sopranos was perfect and retched all at the same time. The show spent all those years keeping me on my toes, because the violence and personalities were so unpredictable, and that ending just made the uncomfortable tension permanent. I mean, yeah, I didn't like it, but I can't argue with the effect. The characters live in a place where the end can come at any time, and in any way. Just like I'm left in limbo wondering just what the hell happens next, so are they. The lifestyle never ends. I think that's a brilliant move.
Cheers is one of my favorite finales for exactly the same reason. I know they are all still at the bar, still doing the same things. That makes me happy to think about.