I highly highly recommend you try to make your decision about which synth (whichever that might be in the end) by playing it in a store, if that's at all possible.

As far as the ION goes, you could definitely e-mail Alesis to find out (I hadn't even thought about tech support, which is a really important issue). Also, make sure you always buy from a reputable dealer, etc.

Good luck! Let us know what you decide in the end!