Best thing would be to go to the bike review section. Last time I looked the Marathon had a solid 5.
I'm very happy with mine. I was originally looking at a Comp with the idea of upgrading some of the parts to XT. By the time we had figured out the upgrade cost it just made more sense to get a Marathon. Everything about the bike rocks. I love the adjustable brain, the integrated shifters, and the F100x fork. It a great race bike but also makes a great all mountain bike. I also have an Enduro. I'm selling it because my Epic can do everything that the Enduro can.
What type of trails do you ride your epic on? I bought an FSR-XC last year when just starting into mtn biking because I wasn't sure I was going ot like it (was a roadie in my youth, hadn't ridden much in 10+ years). The bike is ok, but heavy (31+lbs), the axel fork is flexy (I'm 220lbs but I doubt this fork would be good for anyone over 180lbs), wheelset is heavy, etc ...
I was thinking of upgrading piece by piece but I'm quickly at the price of a much better bike (500 fork, 300 wheelset, some XT upgrades (300-400), etc ...).
I'm in Austin, Texas and we have alot of rocky stuff here, I'm ok with my 100mm/90mm (F/R) travel today, so think that travel wise the EPIC would be ok, but looking to see what others are riding when they say they like it. Smooth singletrack, I figure is a no-brainer ...
I can't test ride one beyond parking lot and that doesn't tell you much