Go here;
http://www.focusst.org/forum/focus-st-wheels-tires/63042-anyone-switch-all-seasons.html
Here's my opinion if you're lazy

I have opined on several threads here but here I go again; I am rough on tires. I ran thru the original F1's in 21k miles. Next I tried some Michelin SS's and wore them out in 28k miles. I was having some wheel hop issues and had tried a turbotech UMM and Boomba RMM to no avail. Another member suggested I try the Michelin AS3's. In short, these cure the wheel hop at the cost of a little reduced traction. In fact, I removed the after-market mounts and there was still no wheel hop. However, I missed the connected feel of the Boomba RMM so I made a hybrid out of the rear part of the Boomba and the front part of the eFocus RMM. It actually increased the wheel hop a little, but not too much.
I put the AS3's on at 39k miles and I now have 60k miles and they are about 1/3 worn. I do not pamper them at all. What you will find is that they have a different nature to their traction limits. Where the F1 and SS tires stick like glue until they break loose, the AS3's lose traction gradually. What I'm saying is that the summer tires contribute to wheel hop in our favorite car because they stick so tight that the engine winds up and hits the limit of the motor mounts. That's when they break loose; then the engine flops back the other direction and they reconnect. But the cycle repeats itself with the wheels hopping like bunnies down the road. With the AS3's there are two factors that make it smoother; the more gradual loss of traction and lower limits. SO rather than hopping the tires spin a little with no hop. There are trade-off's; if you love the "on rails" feel on the interstate, you do lose some of that. Cornering traction is also reduced and exhibits the same gradual release feel I spoke of above. So, rather than hitting a corner hard and letting off the gas and having it swing around and then jerk when it regains traction, there is a more gradual slide and no "jerk" when it reconnects. There is also more tire squall involved. Another difference is the tramlining; the tendency for a tire to pull across the crown of a road and pavement irregularities. These have less of that than the two main summer UHP tires.
So, overall, I think the positives outweigh the negatives and I will keep using AS3's. They ran me about $1000 for four at discount tire, about the same as for the summer tire. However, another option has been brought up in another thread; what about UHP summer tires that are half the price as these? You would likely still have to replace them as frequently, but they wouldn't cost as much. Hmmmm...