i'll just jump on that one as wellPhatboy said:TFI:
only add fuel
is fairly easy to adjust yourself
adds or subtracts fuel
adjust by connecting to PC or Palm
With either you can find setups online and for both you can go to the dyno to have it set up right. The Powercommander offers a lot of options such as mapping the cylinders seperately and the fuel pump utility. From what I've seen , the maps take fuel away quite a bit so the TFI bike will probably run rich at certain rpms/ throttle positions.
The TFI is tuned with 3 ranges of rpms (and the 4th dial I dunno), as opposed to the powercommander that maps all rpms in 250/500 increments at nine different throttle poistions. So the TFI has 4 things to adjust as opposed a PCIII map which will have 99-414 blocks which can be adjusted.
So you can tune it with TFI or fine tune it with Powercommander. The PCIII with a custom map would be more than twice the cost of the TFI. I went with the Powercommader and had a custom map done because I'm just frivolous like that when it comes to my bike ;-)
very happy with my PCM and will be even more so when i get it dyno tuned