What I'd really like is the Arah heavy set. If you've never previewed it on an asura, give it a go, it's like the heavy set is designed for Asura and the rest of the races lose out.
Warrior asura don't really show anything special, but the only reason I'd go for a guardian asura is to whack things with the hammer and knock them back 30'. Sure it works the same for all races, but when your little asura smacks the giant risen across the landscape, it's just more fun. The elementalist can do the same with lightning hammer though, so not required to make a guardian.