Pros:
Organized forums
Solid, but not great CPM ($5-6 when I was there, but mine is now higher with Curse)
Fantastic music library for free (audiomicro.com)
Ability to get upgrade into Polaris if you're big enough
Offer wall where you can promote a certain game in a video for extra money
Referral program
Cons:
Relatively slow support due to sheer amount of people
SLOW forums (at least when I was there)
1 year lock in contract
60/40 split (pretty bad comparing how most networks offer 80/20 and Curse offers 90/10)
Many bugs in dashboard
Auto renews contract if you're not aware of the 30 day notice for terminating agreement (screwed A LOT of people over)
MANY reports of scam and shady tactics
Loss of credibility and prestige after partnering a whole lot of small channels
I recommend stay away from RPM. The cons outweigh the pros and the pros of it can be found elsewhere as well.