Well, I own Guitar Rig 2, 3 and now 4. Guitar Rig 2 and 3 were interesting and useful but noisy. Guitar Rig 4 is free of noise. About time.
This is the shizzle for home recording. Here are some demos of crunchy and clean:
http://www.soundclick.com/bands/default.cfm?bandID=964885
The crunch demo was done with my '77 Gibson Les Paul loaded with Skatterbrane Earthbranes and the Clean demo was done with my 1994 PRS CE22 loaded with Tom Holmes pups.
Signal chain is guitar, Alesis i/o26, iMac, GarageBand and Guitar Rig 4. No processing other than the presets.
Yeah the Guitar Rig 4 version is an improvement from the previous releases, especially the noise factor on the high gain settings. Honestly though I found the amplitube software to be the best in sound and possibilities to edit.
Interesting. I have Guitar Rig 4 and to this day have never gotten it to do anything besides producing silence. I'm pretty good with computers and software. Built two PC's and they run fine.
No luck with this puppy. This is why I made the decision to purchase an eBand.
Guitar Rig 4 uninstalled, eBand in use, problem solved.