Ok the effects are real nice and there is alot you can do by adding effects, controling effect parameters with the volume pedal or foot switch button (CTL). The delay can be set by foot tapping a button when configured right.
Can be tricky to configure stuff as the instruction book aint the best.
Alot of the distortions sound pretty nasty, but it is possible to get a nice distortion although may be a little too processed. Alot of tweaking needs to be done.
Great how it has a global EQ (hi and lo), 4 band EQ section with Q for each setting you make and also an effect which is an even better EQ, might be 6 band with Q, so there is alot of control over your tone.
If you want to stay away from the (kinda) processed distortion you could get a seperate analogue distortion stomp box and im sure you can hook with the GT6.
Hope this helps you make your decision.
I know I am glad I got mine as it is soo handy for saving effects settings and most of the effects are pretty good. But I would go for
the GT8 as it is newer and will prob have better quality (and more) effects.
http://www.musiciansnews.com/guitars/86/hot_boss_gt8_guitar_effect_processor_pedal.shtml
PS: Remember to check the input and output levels in one of the menu's so that your signal aint clipping.
You can hear some distortion tones of the GT6 at the link at the bottom. (all songs but "NOT SEROTONE")