I started paleo on Sept 15 2010, weighing 194 lbs. I lost 15 lbs in the first 30 days and since then I have gradually lost more and more and now I am at 154, total of 40 lbs lost, just over 10 months later. I'm 5'5" 27 yo female, I probably should lose 20 more lbs of fat but I need to add muscle, too, so I don't know what my end ideal weight is going to be.
To compare with conventional wisdom/dieting, on Jan 4 2010 I was 207 lbs (my heaviest) and I started with the whole chronic cardio (running....ugh) low-fat/high-grain nonsense, and in 6 months of being MISERABLE and torturing myself, I lost a whopping 13 lbs, to get to the 194 I started at when I began paleo.
I was a size 16/18 when I started paleo, now I am solidly a size 8, but I do fit into some size 6. And holy cow I FEEL so much better.