If you play with a bonus, don't get too lucky, I believe they have a maximum withdrawal when playing with a bonus.
The max cashout issue is a personal peeve of mine. I never used to mind max cashout when playing table games because there are no jackpots. However, playing slots online has been so much fun over the years, and I can remember my big hits vividly (I try to forget my losses). To take away a majority of the big hits would have ruined the fun. Furthermore, the max cashout, in my opinion, lowers the RTP in an amazing manner. Personally, I'd rather play with a 90% RTP than a max cashout anyday.