Is there a demo to test your setup? Seems necessary to me. I could well bite as it'd be great to mix computer gaming downtime with something creative and personal-growth related, but I'd want to know it works.
There's a PC demo but it is very hard to test as it requires the USB cable. I tried my guitar floor board which has a very similar USB out option, but it doesn't seem to work with anything but the official cable. It is not that expensive (20 euro or so) but without it hard to test.
Personally, I think you won't have any problems - as long as you have a guitar with a working audio out, it should work. People most likely to have real issues would have some kind of HDMI surround processing that introduces a big delay. On my TV with HDMI input and audio on headphones, the default lag setting of 50 (ms?) seems to be exactly right. If you have a setup that you can't control opthey recommend configuring audio over analog, for instance on PS3 you can use an old PS2 cable and configure your audio to come from there, but I doubt that's something you'll need.
My advice would simply be to buy it, and return it if you have any issues that prevent you from enjoying the game. So just get it from somewhere you are certain to have a fuss free returns handling.
I played for quite a few hours yesterday, and reached the rank of local headliner. So far it is quite amazing tech, it knows when my bends are good, sustains hold long enough, palm mutes are done ok, hammer-ons are being used. It is much more forgiving for okaying notes during off time, and you get a full playback of your performance afterwards, which is fantastic. It is also quite impressive that they basically manage to make your guitar sound right for the song just using the in-built amps, pedals and stomp boxes (which you unlock and you can fool around with freely yourself, chaining them as you please. It's almost a good thing they have a slight delay, though if they'd be able to kill it, this would be one of the cheapest and most effective emulated amps you can buy)
If the game had a little more stat tracking and online friends list integration, I'd give it a 10/10. Well, and I wouldn't mind if you could oush the difficulty up manually rather than dynamically, because it ramps up a bit slow sometimes. But main criticism initially was that it ramped up too fast sometimes for beginners, so understandable.