I made MM fondant and use to use wiltons, but I find that the MM fdnt is soooo much heavier!! I tried to make a bow with the MM fndnt and it was to thick!!
now with the wiltons it was fine and dried in like a day or two, with the MM fondant it would take more than a week to get a bow right.
I have used both. I prefer the taste of the MMF hands down over wilton. When I make bows, I use a 50/50 mix of the fondant and gumpaste - you can roll it thinner and it dries a lot quicker. ( or use all gumpaste)
If you like MMF for other things, but Wilton for making bows, then do it that way. There's no rule that says you can't use different fondant for different applications!