It was OK, I wouldn't go as far as to say it was 'crap'. It was a good episode. I would have liked it more if it had been in the middle of a season.
As a finale, though, too much of the previous season was ignored and hence left unresolved. I get that the First can impersonate Buffy cos she'd died, but where does the First go? It lies dormant again I expect, but we're shown nothing except the Buffy impersonation vanish.
I too have a problem about how easy the uberVamps were to kill, although I've read a resonable explanation which did occur to me whilst watching, but wasn't made clear enough.
I think I'm in the minority here when I say that I'm not a fan of all the slayers being 'activated'. I was wondering why early in the season they began to use the term 'activate' rather than 'call', now I get it. They were building up to all the potential slayers being activated, but not called. There are not going to be watchers 'calling' the slayers to do battle with evil. They'll just have increased physical strength and nothing but their peers to take it out on - a recipe for chaos if I ever saw one.