I have one of those cheap J2ME phones, so I can't really use any browsers that are actually any good. The default on mine is unbearably slow, so it's pretty much useless. I use UC browser instead, which is surprisingly good for a little J2ME app.
I have only used Opera Mini and Dolphine and I have to say that they are awesome. That's why I use them daily. They are fast and they don't have many big bugs. They have some useful features which can help you to browse in the Internet more easily. I want to try some other browsers, but I don't think that I can find a better browser than them.