Mrrpm flashes the factory ecu. The problem I see with this is if you go to a dealer and they update your software/firmware on said ECU, then his programming is lost. MrRpm, correct me if I'm wrong. His also does not have a fuel controller included. But, it is much less money.
The Tune monster for the Maverick is a new ECU and a fuel monster. When you buy it with the add-on autotune, you're spending $2,060. Mrrpm's reflash is $500 I think. With the tune monster, you have complete control of all the things that MrRPM will do to your ECU for you, plus timing and fuel. So, they are completely different things. But, an accidental reflash from a dealer would hose all that up I do believe. The TM is an ECM and fuel controller and software for you to modify those things on your own at your leisure. Plus, as you do performance upgrades like more air, bigger throttle body, cams, etc, you can just run auto-tune again to adjust for the additional fuel needs. Steve will initially adjust things like timing for you (since most of us don't know crap about proper timing adjustments) and then you just go ride with auto-tune to let the fuel tables adjust accordingly. It's a pretty painless and quick process to get the fuel tables dialed in with auto-tune.