NATS and
MPA3 are probably the two best adult affiliate-tracking and sales reporting, tools on the market.
I don't have any experience with MPA3, but lots of experience and heard many user comments about NATS. It's a great system with fairly concise reporting and excellent tracking. However, it is painful to setup, eats a lot of resources, and can be difficult to maintain.
Can anyone share their experiences with MPA3?