I’ve been using both for about 6 months now. Betfair definitely has better odds on major markets I’m seeing around 2-5% better value on NFL spreads and totals compared to DraftKings and FanDuel. The commission is typically 5% on net winnings, which sounds high but when you factor in that traditional books build 4-5% margin into every line, you’re still ahead. NBA has decent liquidity on game lines but player props can be thin. The real advantage IMO is not getting limited I hit a good streak on a regular book and got restricted to $50 max bets within a month, meanwhile my exchange account is still going strong with no limits.