Just to offer a different option, I'm at 566 and my raid team is just now lazily making our way through heroics. I still find that subtlety is the best single target damage spec with my gear, though the gap between it and combat has shrunk considerably from say 10 item levels ago. Rogues in top end guilds seem to find pretty much unanimously that combat is superior single target at their gear levels, so I imagine the switchover point will come for me pretty soon. But up to about 570 or so if you're good at subtlety then it's an option depending on what your raid needs you to do on any particular fight.