I have a tune boy for my Triumph and it ROCKS!!!. Does exactly what a power commander does,(and more) in fact, you can download powercommander maps from their site and import it into the stock ECM. It can diagnose engine light problems and change a lot of parameters that only a dealer would otherwise be able to do. You can make custom maps, Adjust timing, throttle position ect....very powerful program. The menus are great and there are a lot of other features that I am unable to use due to the complexity of the program and my lack of knowledge. Tuneboy fully supports their software and supplies constant updates. Basically you get a program that can be used for a large lineup of bikes (I didn't know this but, the front and rear cylinder have different maps on the Buell) and the difference is you pay for your personal ECM code.
Downside? Price. Expensive for an ECM programmer, but if youre smart enough to use it, (all of it) definately worth it.