The only really comfortable pad I've ever found is the POC Bones... They're properly lobstered and articulated, they don't need to be firmly strapped on- they naturally move with you so they just need 2 very gentle elasticated straps and a loose, thin sock- less sweaty and enclosed. But despite all that, they don't move at all in a crash, and they're very protective (and have huge coverage too, almost all teh way down the exposed side of the forearm)
Soft pads tend to need to be held on tight and are always more enclosing.
Stormtroopery, though, and very expensive. I feel a wee bit silly wearing them sometimes on trailbike-type rides but I am brittle and it makes no sense to buy a less protective, less gnar-looking pad if it's hotter and sweatier.