I agree with the above. I took a few shots at 100NL and did really well, so I moved up for a while. I took a turn for the worse at about 3000 hands. I found myself getting caught trying to buy pots and not being able to get away from big hands, so I tilted away a lot of money. I started to be one of those guys that I love to play against. Another huge factor is that the 100NL players don't seem to pay you off nearly as much on your big hands. That was the problem, I was losing a lot on my second best hands, and not winning much on my best hands.

Bottom line, 100NL is worth a shot, but you're going to have to play consistent good poker. When I moved up, I was beating 50NL for ~15PTBB/100 over about 10K hands, FWIW. Be ready and willing to admit to yourself that you might be out of your league and maybe you have more to learn still. That was the tough part for me, because I overvalued my short-term initial results.