Copypasta from the email I sent to a professional musician friend (who will let me record his gig Thursday, if I can brave the cold and ice on my motorscooter), who ordered one (at the great current B&H price of $30 delivered):
"Got the iM2 and love it already. The app is a little skittish, but the mic works with all apps I've tried (Garageband, Tascam PCM, FiRe and iPro Recorder).
The mic also works for video recording. when you shoot landscape, you'll need the workaround below for true stereo orientation (cord).
Took a while to be able to monitor. Don't plug in a headset that has a mic.
There are issues, but you have a portable (I checked it out online....its a real mother) so you know about handling noise, etc.
The mic won't fit with a case on. The work around is go naked, of course, or get a dock cord, which I have on order, to isolate the mic
I also ordered a lightning to 30 pin adapter cord for my Mini. Now that I think of it I assumed yours is not an iPhone 5. If it is, that would be the work around.
The Tascam app is hard to find with an iTunes search so here's the link:
Its pretty good but some limited function (not multi-track) but download it for sure. You can play with it to get familiar until your mic comes.
https://itunes.apple.com/us/app/pcmrecorder/id481055155?ls=1&mt=8
I'm looking at this one ($10) has unlimited tracks and a lot of other features
Way more than I would use.
https://itunes.apple.com/us/app/prostudio-music-recording/id361109353?mt=8
The iM2 works in Garageband for iPad, but I can't figure out how yet to set Garageband to record without stopping at a certain number of bars. Help a brother out if you know.
This certainly isn't the equivalent of the portable you already have, but its a pretty cool gadget. "