Handcent is pretty good. The only thing I don't like is that when I receive popup notifications from group messages, it just shows a play button arrow instead of the message. Very strange. It also has the same issue with sending videos because I use it as my main text messaging app (by the same issue, I mean the issue this topic is about, not the issue I just mentioned with group messaging).
I really wanted to give go SMS a try, but it was going very slowly, basically freezing, during group messages when there were a lot of texts. So when people would send me tons of messages at once it would be impossible to reply until they were finished talking. That doesn't really work for me so I'm sticking with handcent for now.