Ugga Bugga offers the highest BetMGM payout at 99.07% regarding slot machine games. Mega Joker, also by NetEnt, comes in at a respectable second with a 99% RTP. NetEnt's Jackpot 6000 and Thunderkick's Uncharted Seas finish second and third with RTPs of 98.8% and 98.6%, respectively.