The Cobra unit is plug and play. Simple, stratightforward, but you have to settle for what it does (I hear it does pretty darn good). As you mod the bike, the PowerAPro will adapt automatically. You just can't tell it what to adapt to.
If you like to tweak and tune and try different things, the PCV is what you want. You can just get it tuned and leave it alone, but you can also tweak the tables using software you download and a USB connection.
I have added the Autotune to my PCV so I can tune the air-to-fuel ratio (A/F) and make it run the way I want her to. You if you have the Autotune, it will automatically re-tune when you to whatever A/F you have it set for when you make mods.
If you don't like messin', just get the PowerPro. If you like to mess, are a bit computer savvy, and aren't afraid to take responsibility for the tune of the engine. get a PCV and Autotune.