If a program offers PPS, there's no guarantee they're going to have the money to pay the webmasters. Especially with visa regs, chargebacks and the scrubbing going around nowadays.
If you open an affiliate program with PPS, be sure to have a clause in there that states if a WM doesn't convert or rebill above a certain level they'll be bumped to revshare and they'll only be paid for what they really earned.
It's only fair
