Hi
@DownAndOut , I moved to nl20 on Microgaming recently and have found few differences as far as the actual games are concerned.
I think a few less spews is probably correct but not a lot of difference. Use sensible game and seat management and if you feel your game is good enough to beat nl10, then it should be good enough to beat nl20.
I don't know if you play anonymous or regular games though, the regular games can be a bit of a regfest but when they do open up they really open up!
Anonymous tend more towards tight/passive, but you may find yourself in a preflop war with the regs if you hit the wrong table, they can get quite aggro preflop but it all goes fairly honest postlop. If you like aggro games that's fine, I personally prefer the 40/4/2 guys and good position!
The traffic from PKR has vastly improved the pool to, so plenty of games available.
Simply put, if you beat nl10, you can beat nl20, just avoid me please, I need the money.