Made the move from a (very) old E2. I bought this online without having ever tried on a Mavic, based on their product description and sizing chart, and it fits really well. Combined weight and fit, I can barely notice I'm wearing a helmet.
I ride solely XC mtb now, and their Ergo Fit/Ergo Hold design really locks this helmet down on my head. I don't notice any movement as I'm bouncing through a trail.
I guess if your head is the right shape, this helmet is well worth the investment, and doubly so with the discount at Backcountry.