Should I buy Guitar Hero 2 for Xbox 360 even though I have it for PS2?

Ok well I have Guitar Hero 2 for PS2, and I love it! It's a great game that really never gets old. I got a Xbox 360 this Christmas and found out that Guitar Hero 2 was coming out for it. Then I heard about the improved controller, exclusive songs, the much anticipated downloadable content, and those addicting achievements. So this really got me interested in buying Guitar Hero 2 again, but this time for my Xbox 360. The only drawback is this time, I have to buy the guitar. The total will set me back $90. So my question is, do you think it's worth buying Guitar Hero 2 for Xbox 360 even though I own it for PS2? I realized I could use the guitar I get form this one and the guitar I will get with the next one to use for co-op.