It won't be much different from the other pro guitar setup already out. Just instead of buttons it'll be strings. From what I see the notation is a little hard to read on the fly, so you'll have to get used to that. Also nothing about the game teaches proper fretting or picking technique which can hurt in the long run if you're serious about playing guitar.
The biggest issue I see with it is that most people who are used to playing rock band are used to being able to pick up the instrument and reacting as you go on a new song. With this, even on the easier difficulties you will have to practice a LOT and most likely slow the song down to see the notation, and then learn the fretting on the guitar. There will be a lot of repeating the same section over and over again until you get it. In other words, this is a mode you play with patience and probably by yourself more often than not. It doesn't seem to be good when you're jumping from song to song with friends. You pretty much have to know the song ahead of time as it's quite difficult to figure out full speed on your first go.