Currently I have a Casio G'Z'one Brigade. Pretty awesome, other than the fact that it isn't a Smartphone. I've abused this phone like it was a small rubber ball, and it just keeps going. Great conversation piece. And what I find most useful? You can text from in a Pool or hot tub, a rather important feature if you're 16. What nearly killed me a few weeks after I bought it, they came out with a Droid version. Stupid me.
A couple complaints
-It is hinged backwards compared to all of the other QWERTY flip phones I've seen
-Predictably, It is quite large. That doesn't bother me, but for others it does.
-The "Clear" key also activates the Nuance Voice Control, which gets annoying after about the 5th time you've accidentally pressed it too many times.
-Front screen is quite small. And Black and White only
Good
-Pretty much won't break, I've dropped it from the top of a 3 Story house, it was fine. Taken it in the pool many times. Still runs brilliantly
-Has an option for an analog clock on the front screen. I like this.
-It has a light above the front screen which flashes different colors when you get a call or text. Useful in class when you dont want it to ring, but still want to see someone tried to contact you.
It will probably get replaced by an iPhone 5(or 4S if the 5 isn't out yet), as my contract runs out this upcoming December.