well, you'll find the m-fil has a hefty amount of power, but not so powerful that you lose lots of control. your head constant beam is probably quite heavy so the m-fil is going to feel very light.
here is my review on my m-fil (stock right now):
forehand:great power and tons of spin. I had a lot more pace and my buddy said it felt a bit heavier. plenty of racquet speed since i spent the last week using an old prostar widebody.
backhand: definitely improved it. I had plenty of down the line back hand winners.
slices: like topspin, there is a lot of backspin on slices Stayed nice and low. Most were about shin height, a few around ankle.
serve:
great power and loads of spin, mediocre to good placement. I couldn't get right on line shots but they were pretty close and consistent.
return of serve:
great return of serve, can easily control the direction and still go fairly deep
volleys:
stable, maneuvrable, and ok for reflex volleys. Only problem is when you frame it. Kind of jarring when that happens.
Overall, there was a huge improvement in my game. I play w/ lead tape to make it heavier as i find it light as a feather almost.