Moving up the limits

[moving shapes]

Been playing for about 2 years - seriously for about a year. 3 months ago i started focusing on online cash games. I started at the NL10 game and am now moving into the NL200 game. I'm playing shorthanded only now.

All the transitions from limit to limit have gone reasonably well. NL200 seems fairly beatable.

Just wondering if there's a limit that gives a lot of people trouble - that the average player can't beat.

Do the difficulty in limits depend on the site for the most part? I play on pokerroom.com

Thanks