The only thing that people really seem to find wrong with the FSP is long term durability (cracking poorly designed headband with cheap materials), and the fact that it's made to be a disposable headphone with glued on ear pads. The driver defects that seem to happen occasionally that ruins the sound is another red flag.
With Focal's typical pricing on most of their products I'm pretty sure $350 is quite disposable to their regular clientele. Heck that would be just the tax for a lot of their products.
People who want a long term investment out of their headphone purchase are wise to stay clear of this particular model IMHO.
ehehe. I actually had the chance to get an HD 800 (a $1,500 headphone) for $400 (since it's not in the best condition), but since I am moving in a few days, I have to make sure my living expenses are covered and missed out. Anyway, I expect the FSP to be totally outclassed by at least a few summit-fi headphones. ^_^