Surly Steamroller owners...

Ed, wash your mouth out.

As for the rest of you...
The cross check hus sliding road drop-outs, braze-ons for racks and mudguards, and different geometry which includes a slightly lower BB.
It can be run as either a fixed or a single-speed, but I would definatly want to keep a brake on it thanks to the slack down-tube angle. Personal preferance though.

from my reading of the surly webby, the steamroller has 70mm bb drop whilst the xcheck has 66mm? coupled with larger tires that is an inevitably higher bb on the xcheck?