Addiction... YES!!
I am no pro at this game but it is very addictive. Use the tutorials.. and make sure to practice lots and go through the songs on easy first. I am getting better everytime I play and am currently almost through the medium level.
I personally think that is what makes this game so awesome... is the challenge. Its hard! But thats a good thing. I know people are thrashing this one on expert and all that stuff but to the average gamer... good luck picking this one up and starting out that way! Thats the way it should be though. The multiplayer is incredible as well. Hook up with anyone and challenge them or play with friends... awesome awesome awesome game!!