Provides good elbow protection. Forearm protection is also pretty decent. I have fairly long arms and it covers almost up to my wrist (close to my body armour suit).
My arms are also somewhat slim which makes elbow and forearm armour a challenge; they always tend to slide down my arm. These don't do that and I don't have to tighten them down so tight to where I'm losing feeling in my fingers!
They breathe OK and they're thin enough to where they fit under my jersey (long, short and 3/4 sleeve). I'll sometimes wear these when I'm riding a really technical XC trail.
The only negative would be for those who have slightly wider arms. It could be too tight of a fit.