Well i have a choice of these 3 i have got both the demos for the GR3 and Amplitube, what do you think is better for me to use?

I like the fact that i can use any effect i need really in Gr3 but i find the sound isn't as good,

But do you think GR3 is better than a 15x cube? or amplitube, i'm just trying to see what other peoples thoughts are as i can't decide either
I'm confused. Are you comparing two different pieces of software and a Cube? Are you wanting to replace your Cube? I've heard good things about GR3 but never tried it. If you dont' really need an amp and just want to play through your PC and record, software is sometimes a nifty way to go especially if you have a decent interface and/or sound card.