The only problems that could arise from this is the fear of hacked versions used during tournaments. I have the feeling that altought this will be great for casual play, if people try to use it for dice rolling etc. As a side note, some make a TI-86 version before i have to. I know I will use it. As far as PC's being cheaper than Mac's, you pay for what you get.
Quality is always more expensive.
I'd be very interested to see something like this made for Windows. I mean we got Apprentice, but this is very nice. It does dice, life counters, coin flips, and keep track of cards in library, hand, graveyard and removed from game. First of all, from the screenshots, your software looks awesome. Have life totals for you and opponent.