Strangely enough, I disagree completely with those who like Stars better. Everyone has their their preferences...
I like FT better, and I've played there more over the years... I've also won infinitely more on FT than Stars, but that just feeds bias, and shouldn't be used as a metric (i.e. "I run worse on Stars" and other meaningless stuff).
Some of the things I dislike about PokerStars are aesthetic (I don't like the sounds & graphics as much - yes, if I went through the trouble I could customize).
Saying that either is "absolutely freaking terrible" really isn't constructive. They both have their positives/negatives. Given that they are two of the largest sites, their competition is causing them to improve constantly.
There is a lot to like about Full Tilt. I like the pot button. I like rakeback. I like data mining. I like the third party software support, like SixthSense and Full Tilt Shortcuts.