Definitely consider the stabilizers, costar on the CM Storm, cherry on the Leopolds. General preference leans towards the costars, personally I find them much more solid feeling, my ducky has cherry stabilizers and like lightsout mentions, it feels a bit mushy, it's not a huge deal, but I definitely prefer the CM Storm.
New leopolds are coming, the FC700R, there's a thread on them somewhere, I think the major difference was thicker caps.