I should post a disclaimer that I've grown to dislike GW's skirmish rules as I find them too random. In the army games the buckets of dice you toss around tend to even out the odds, but in the skirmish game you're getting only one or two dice per model and you only have around a dozen models. Add in the campaign elements and it's easy to find yourself falling way behind after just a couple unlucky rolls. In theory there are some mechanisms to try to balance things a bit when this happen, but in practice they don't really work.
I am in the minority on this though, and most people I know who've played Mordheim or Necromunda or Blood Bowl really like them.