GuitarBots is a relatively new game that recently came out of beta. I heard about the game before and had the pleasure of playing it today.
First of all, the best thing about this game that makes it trump Rocksmith in every way is that it is free and you do not need a special cable to play it. As a guitarist who regularly records myself, I was appalled that I could not use my USB audio interface to play the Rocksmith. With GuitarBots I can and I can even use my acoustic guitar to play with any microphone.
No external equipment is needed, either. All you need is a laptop with a built in mic and you are ready to rock. At first I was a bit taken back with the price of the full game. The free version does have one limitation, which is a system they call picks.
You earn a pick every 10 minutes and for other in-game achievements but it costs one pick to play a song and you lose a pick for every part that you successfully play with a 3 star rating. You can never have more than 10 picks and never less than 0 so it is a fairly balanced system.
If you are at home all day then you can play a song every 10 minutes, which is perfect for me. If you only have a few hours in front of your PC to practice every day then you might be better off buying the full version.
There are tons of practice exercises and tons of full songs made by the growing user base and the developers themselves.
The game costs either $20 a month (Not worth it) or just over $80 for a year and just under $120 for 2 years.
If you play the game for a year straight, you will greatly improve your guitar skill, so I recommend it. After a year or two you should probably move on to other things, but a solid year of practice with this game would be good for any guitarist.