I was just about to ask the same question
At first I thought that this is a no-brainer. The money's got to be in revshare, so I used only reveshare codes.
Now, on my first 5 sites I've had a total of 9 signups, and I'm super happy about that
However, 7 were for revshare and only 1 of those stayed beyond the initial trial

So it seems like I would have done much better with PPS... unless that single one will stay as a member for 5 years or something I guess
Then again, if a sponsor is willing to pay $30 for a 2 dollar signup, it must mean that they average much more than $30 per signup.. right?