I've had one for over 5 yrs now, it's a great unit for FX as forbidden said. Like all Boss units the preamp models are a bit naff but if you run a POD in the loop and it's awesome.
You can buy mine if you are after one, since I'm not recording much anymore and am concentrating on bass playing it's not getting used. PM me if you are interested.
not just Bolt Thrower , Mick Thomson of Slipknot as well!
The cool thing about it, it as a real preamp, so you can plug it direcly into a power amp and you'll get a lot of power. Exacly why I hate my pod x3 live and want one of those to plug in my mesa 50/50.
The other guitar player in my band as one and he kills me with power every jam. (same setup exept preamp)
Not a fan of line 6 since my mesa 50/50, its only good on solid state amp.
Had one in the loop of my 5150. Great Unit. Preamps are a bit meh ;-)
Afterwards I bought the GT-Pro. Soundwise there wasn't that much difference too me.