I noticed the VG-8 got mentioned earlier in the thread.

The VG-8 is quite different from the GT series. It's a guitar modelling system, not a simple multiFX unit (I have the newer VG-88). First off, you'll need a hex-pickup on your guitar (a Roland GK-2AH comes with the VG-88, normally, or use RMC piezos or a SoundGarage hex humbucker).

Essentially, the VGs let you make your guitar sound like any guitar you want, from a Strat to an LP to a 12-string Rickenbacker, to acoustics, classicals, bass, some synthy sounds and more. It's not a guitar synth though; the sounds are created by processing the signal from your guitar, they're not just samples that are triggered.

The VG-88 has an FX section that's essentially a cut-down GT-3. It doesn't have things like the auto-riff and the other slightly gimmicky features, just compression, wah (which, if set up right, actually sounds very good indeed), EQ, modulation, delay, chorus, reverb and noise gate. It also has the same amp models as the GT-3, though there are rumours (from a reliable source) that it's about to be updated (firmware upgrade over MIDI) to add all the GT-6 amp models and FX, plus better bass modelling.

If I was in the market for a new processor, I'd either get a VG-88 again or a GT-6, some anodiser stripper and some spray paint. That gold colour is just tacky.