I did use Moose prior to SqueezeCenter 7 and it was definitely faster. Haven't tried it of late. The one slight problem I have with the new SqueezeCenter default interface (under Windows Vista) is that it seems quite sluggish and that can be annoying when you're browsing for music. While the new default interface is definitely more intuitive (and prettier) than the old Classic or Fishbone, the older ones definitely seem faster. I'm sure it's still evolving.
I'll give the latest Moose a try and report back.