Hi,
I have a number of them,
Touch OSC is about the best and most complete out there, though more templates for the iPad would be awesome.
Eyosido is just too freaking hard to setup and get working, you'll need to have a masters in "how to work with complete confusion"...
ITM makes some cool things, MCU (Mackie control unit) Midi Lab, and a few other cool toys.
Pro Transport is not too usable in my experience.
AC-7 Pro is like a Berringer BCR 2000 and works exactly like one
Those are but a few of the apps one can get for the iPad that will control Logic Pro in some way. Just go to the Apple App store in iTunes, and enter music and controller into the search engine.