The '01 RK is the MM, and IMHO, there's not a thing wrong with it. You're much less dealer-dependent than with the Delphi, and you don't have to labor under Delphi's heat management system. If you want to build the engine, you can make good power, and the system accepts the Power Commander. Its main drawback is that if you want to make more than 110 hp, you're probably not going to do it.
Don't get me wrong, the Delphi is also a good system; it's more comlpex than the MM and measures things more finely, and it's gotten a lot of very good reviews. But if you're inclined to work on things yourself, the Delphi EFI system was one of the first of many steps in making the HD owner more dependent on the dealer. For example, only the dealer can set the idle on the Delphi.
If you've found a bike that you like, I wouldn't let the MM system stand in the way of getting it.
Ragnar