I liked GLTerm. It was a lot better than the stock Terminal app. It passed PgUp and PgDown properly, as well as the F keys I have bound in screen. It's faster than Terminal, which isn't an issue unless I'm running QuickASCII, the text-mode Quicktime Player.
Unfortunately, GLTerm doesn't live with the video hardware in my iBook 700 very well. Once the screen saver kicks in, things start getting corrupted. First, GLTerm windows fill with mostly-white noise. Ctrl-L fixes that at first, but after a while the windows go solid white for good. For a while, you can close it and open a fresh one that works, but then those come up solid white. (It still passes input okay, so it's possible to gracefully quit or detach from what's running inside the white window, as long as you know the state of the program.) Logging out and back in cures it for a while, but after a while, the system hangs on logout. Eventually, the system will hang all on its own.
The sad thing is, GLTerm is shareware, and I paid for it. Michael Pollet's web page promises support for paid users. Unfortunately, I have yet to see so much as an auto-reply to mail I've sent. It's the first time I've regretted paying for shareware. I'd discourage anyone else from it. iTerm has all the same features as GLTerm, plus it doesn't kill the system. And it's free.