Was on Mastertune's website last night. Now I know the difference between it and PC. I'm familiar with HP Tuner and how it works (I have a custom tune in my 2006 SSR that was done with HP SW.) Looks like Mastertune operates the same way with bikes...edits fuel tables in the factory ECM. Looks like I can also use the software to view fault codes. I assume PC cannot query the ECM for fault codes? You've just about convinced me to go the Mastertune route.
No, the PC cannot "talk" to the ECM as do the TTS, SERT software. The TTS works like a SERT. In the long run, you'd be better served with a product like the TTS, though the PC does just fine. The only downside to the PC is that if it ever takes a crap on you, you must remove it and then you're back with whatever is actually in the ECM with regards to programming. Not many PC's take a crap, but it has happened. Anything can fail.
Yet another option would be the Rev Performance
http://www.revperf.com/Precision/index.html I am not personally experienced with it, but others here are using it with success, so it is a viable alternative.