My win rates from Poker Tracker, all are limit games:

.02/.04 - 145 games, 3.1 BB/100
.05/.10 - 1,890 games, 5.88 BB/100
.25/.50 - 1,700 games, 3.91 BB/100
.50/1.00 - 3,501 games, 4.68 BB/100
1/2 - 695 games, 1.01 BB/100

My usual game, .50/1.00 has been as high as 6 BB/100 and as low as 1.5 BB/100. It is currently a tad high as I have been catching good cards the last 500 hands or so.

Notice how low my win rate is at 1/2...I suspect the skill level increases exponentially from .50/1.00 to 1/2. They aren't running over me, but I'm not running over them either. All of those hands are from Interpoker.