For protection and value, look to 661 first. There are those who will tell you that Dainese is the living end - - Why? Because it's expensive? Give me a break. Until recently, I wore hockey shoulder pads (after a nasty crash earned me a broken collar bone, three cracked ribs and a punctured lung) because most everything on the market for downhill was a joke. Most of them are glorified roost protectors borrowed from motocross. Or the hard-shell contact points were way undersized for a real high-energy crash.
661 now makes their Pressure Suit with some substantial shoulder protection besides all of the good arm and spine stuff. Look particularly at the SP-1 (Steve Peat) model. If you prefer the hard-shell (M-X-style) armor, the Defender is about the only one out there with suspension in the shoulder caps that amount to anything. Also check out the new Ricochet hard-shell articulated knee/shin. Go to www.vsportgroup.com
The one caveat on 661 gear is (as other posters warn) it runs large. I'm a scrawny 6'-1" and the straps on the elbow/arm and knee/shin are too long for me. But I'm leery of going down to a small. I just shorten the straps. Location of the guards, etc is right on.
Fox is OK stuff, but is mostly carryover MX gear - - light on energy-absorption suspension. 661 is as good a value and better suited, IMHO.