[AaronBrown]

I'm not sure there's a general answer, some people seem to take more naturally to one or the other. It also depends on the type and level of competition. But if I had to guess, I would say it's harder to avoid losing a lot of money in no limit, but harder to win consistently at limit. Therefore a good no limit player would find it harder to move to limit and keep up her win rate, than a good limit player moving to no limit. But for average or poor players it would be the opposite. An average no limit player would find it easier to break even at limit than an average limit player would moving to no limit.

Generally people get experience in both types of games before getting really good, so the conventional wisdom is no limit is harder. You can have leaks in your game that are only annoying at limit but are disastrous at no limit. But people I know who have switched later in their careers seem to find no limit easier.