I find this card completely worthless. To remove GBA support? with that, it removes the compatibility for GBAs that people have, and the whole point of having a Slot 2 solution. There is no real need for rumble, for me, it is a waste of money.
Now I own a Supercard SD, works pretty nicely, except a few, but I feel switching to a M3 card will have to be my best move. I wouldn't be surprised if they didn't release a rumble model of their own with full support of GBA, etc. That would destroy this so-called Supercard.
I just see this as a poor decision by romman, I doubt he will remvoe the old product line any time soon, he would lose a large customer base that way.