Day, as he goes on these forums, pointed me at Savitar last night. I had been using and, on the whole, enjoying Cantrip before that. Well, let me just say: I'll be in Day's debt for a while -- Savitar is awesome!
Cantrip has some nice features, but it also has some annoying bugs. Since its development has stopped, those bugs will never be fixed. That made me a little nervous. I'm very glad to have found an excellent OS X client which is still being developed. Also, the feature I liked best about Cantrip (RegExp support in triggers) is implemented perfectly in Savitar. If the OS spellchecker is implemented soon, I'll be living the high life. :)
I'm sure I'll be in here with feature requests a lot as I continue to use Savitar. I just wanted to start my posting record with some heartfelt appreciation for the developers. Thanks for the great client!
Taurindur @ Elendor