This brace is very light, from the first time out once I started riding I completely forgot it was there. Comfort is excellent, it doesn't interfere with you or your helmet. Leatt supplies it with three sets of sizing hardware which is very appreciated especially when there is nowhere local for me to try it on. Padding is easily removed so you can clean it. The brace has multiple adjustments that are very quick and simple so it is easy to fit it to you and your body size /type.
None so far.
I will tell you this, it just works, I can attest to this personally. Recently on 5/19/13 we had a group session at our local spot. We were all hitting a jump called the ski slope. It is a large wooden feature that you double over the backside on to the lip and boost. I have done it many times only this time I came over too far went off the side of the ramp crashed through some brush sending me tumbling. I rolled on my head and the Leatt did it's job, so much that two of the guys watching said "you were like slow motion and saw it save me" They went the next day to order one. Thanks Leatt!