I have the Riff tracker, and it works good enough for me, the instant drumer feature has just a few rythms and you might want to upgrade latter on,
Stay away from the guitar port becouse you wont be able to record to a CD using the included software alone, you will need another software such as Sonar or other.
The riff tracker comes with a different prog. that allows you to burn your music onto a CD. And it includes all the sounds and effects of the Guitar port.
I use the riff tracker to record my songs, jam along using the drumer or making my own tracks.
Another cool thing is that you can bring a song from a CD to the program and play it at half the normal speed, what is known as riping a song. It also has a built in tunner, metronome, sounds, etc.
If you go for this make sure you have a pair of good headphones, they come handy in the final mix.
Now I wanna go to my local guitar store to check out the XT.
Keep those fingers playing.