I've tried just about every one.
First off, they don't depreciate very quickly, so you might find that you're better off ordering a stripped-down version with just a few sporty options rather than a gussied up one that they have on the lot. We've found that we can buy a new stripped one and trade it in after 2 years, losing about 2500-3k per year---which is cheaper than a lease for the mileage we do.
I like the 2005-2006 years for the earlier cars. The MCS has a LSD option after 2005 and the MC has a better Getrag transmission.
As far as the later cars, they're both good.
Options to look out for:
MCS:
LSD
Sport suspension (on R56)
MC:
sport suspension
sport seats
Note: avoid the big sunroof..it weighs a ton (about 100 lbs)