I think Andy Murray's the worst match-up for him amongst the top 4.
I was okay/excited about his match against Fed (knew he had a chance) and would've been just a little less okay/excited if it was Nadal or Djokovic.
But I seriously think Murray is the best 1st serve returner of the bunch... hoping for Istomin to take him out.
At the same time, Murray is the worst of the big 4 once you get into a rally, and won't be able to exploit Milos' weaknesses as well as the other 3. Milos was able to hit with Federer, but Feds was able to move him just so to take control.