Heck, why don't you just buy all 3 so you can shoot them enough to really tell?[8D]
While you're at it, why not buy the Outback too? What's another $600? Then you could be really sure, or your shooting could be totally messed from constantly analyzing too many bows.[8D]

On a more slightly more serious note, I would think the Patriot gives you the best features of both the Liberty and the MM. It has all the speed (or a little more) that the MM has, and the slightly better stability from the longer riser like the Liberty. I know that lots of guys really like their short bows these days, but it's hard for me to comprehend how a sub 34" ATA bow is going to be too long to shoot from a tree stand. All 3 are very nice, as are most bows out there today. Hope you really enjoy the bow that you choose to buy.