Its certainly no worse than learning a new OS or language, except in that if you really, really mess up it can take more than a reboot to fix it! So the "measure twice, cut once" principal is important.

I think that the HP Pro is more comparable to the EFI Live product, in that it has the external A/D inputs and logging capability. Closer in price, also. It seems that HP tuners has a pretty active forum, on the other hand there's an article on the EFI Live site about "auto tuning" that's pretty good - although it takes a couple passes to get through if you don't have the stuff handy.

One thing that's confusing to me about this is that both products consist of two parts: a hardware interface that is used to communcate with the car, log data, etc. and a PC program that is used to manipulate the data downloaded from / to be uploaded to the car. Most of the documentation doesn't distinguish very well which part its dealing with!

Personally, I don't like the "buy a tune then tweak it" philosophy. That doesn't do anything to shorten the learning curve. I've been in that sort of position a few times where manglement has had a vendor install something then expect me to support it as if I had the knowledge I'd have gained during the installation. This results in more of a learning cliff than learning curve.