I played SNGs almost exclusively between July and October of this year logging several thousands. If you use Party or Stars, there is a program called SNG Tracker which logs all your SNGs and makes all sorts of nifty graphs.
I played 8-10 at a time at the $33 and $55 level. I don't remember the results for each level, but the cumulative was something like 38% ITM, 18% ROI. I have a hyper aggressive bubble strategy so I won like 15% of all games, but actually had more 4ths than 3rds...i still think the math works out in my favor.
Best of all, each SNG averages only 34 minutes for me, so your hourly rate can really become something pretty decent.
E