Back in September I bought an ION Drum Rocker, and I gotta say, money well spent. Since switching from Wii to PS3 and getting an ION kit, I've played Rock Band more these past few months than the past few years. Anyways...
The reason I bought the ION kit was because I wanted a cheap electronic drum kit for when I move out next year since I won't be able to bring my acoustic kit. This is where I'm at right now:
ION Drum Rocker Core
3 Pintech Cymbal package from RBP
Yamaha KP-65 and KickWire
Now I realize I need a drum brain, but I'm not really sure which drum brain I should be looking for. I did a bit of googling, and what I found was the Alesis DM5 module. All I will be using this kit for is for practice, so I don't need anything fancy, but I want one that will also work with the MIDI Pro Adapter. Also, I was reading on Docs RB Mods that only certain brains support open/closed HiHat, so I would sort of want that as well.
TL;DR - Best drum brain for ION kit that works well with MIDI Pro Adapter and supports open/closed hi hat