I just recently went through this shopping deal myself. I tried on a very wide variety. I went with the HRP myself, as I had one before and really liked the comfort and protection of the raised shoulder. I really liked the No Fear one and nearly bought one, but I wanted the "arm guards" for woods riding. As for the Acerbis unit, I thought this was "the one", but it didn't fit "me" well :( . It may be fine for you though, but I would recommend trying them (this goes for all, for that matter) first.
Hope this helps, and doesn't confuse the matter more...