It depends on the limits on each one. If you can only get so much for the 20%, but the 16% is permanent, then go with the rebate if it could potentially be much bigger over time. Remember also that you can lose here while winning elsewhere. It's all about e.v.
pinny did offer 5 percent back on losses when you went thru an affiliate. So if you lost 5K for the month at pinny you got 5 pecent back from your affiliate=250 dollars from the affiliate. So for people who were using pinny to arb/clear sportsbook bonuses then you were set.
5Dimes offers a 15% Cash Back Rebate on net losses, posted twice a year, 2 weeks prior to the NFL Preseason, and 2 weeks after the Super Bowl. They're definitely my new favorite book since Pinny went away.