My Edirol PCR-30 is a nice keyboard with full features BUT due to its size, spends more time in the closet than conveniently attached to my DAW. Since I tend to noodle out parts on the keyboard and then edit them in Logic 9 or Garageband, this Akai MPK mini is a much nicer option. I got this about 3 months ago and it spends most of its time conveniently tucked above my iMac keyboard.
The MPK mini offers a very complete 25 key, velocity sensitive keyboard, 8 drum pads, arpeggiator and 8 configurable knobs that I can use when twiddling Low-pass filter cutoffs, Resonance or whatever you want to program the knobs to. The only missing features are the tone wheel and bend control.
I also can use this keyboard with the iPad camera connection kit to feed CoreMidi directly to my iPad when working mobile.