Multi-effect pedal-very robust at Boss
COSM-modeling technology (which seems to be more to the point)
Log-MIDI IN / OUT (possibility to connect sequencer or other GT8 to swap patches)
-Digital Output (for recording or otherwise)
-Effects Loop (SEND / RETURN)
-Headphone output (can also be swung to a card multientrées)
-Control of the amp via Jack 6.35
-Can be connected pedal or footswitch aditional expression (like Roland EV5)
Simuleurs lot of preamps with a lot of channels and the Dual Rectifier 5150 Peavy

A wide range of overdrive / distortion pedals incorporating most of the BOSS and a compressor
Classical effects also DELAY / CHORUS / REVERB (whose characteristics are parameters), WAH, Phaser, Tremolo, Flanger, autowah, Slow Gear, Ring Modulator, Humanizer, feedback, Sitar Sumulator, Defretter, Vibrato,
-EQ (parametric for high medium and low medium)
-Possibility to change the parameters of existing patch (The strong point but requires hours of work)
-The display is screwed up and readable (you can adjust contrast)
-Tuner

UTILIZATION

The manual is provided in English, arghhh but it seems that there is one available in French on the Net
... Expect a few hundred pages auf if you go out of an old GT, your task will be facilitated.

Dispostiion of the knobs and logical enough, not hard to dip, I do not think there too many buttons as some think. If we do not linger to return to the parameters pushed, Yes you can find a very nice type fast enough MESA channel 3, nu-metal in your fu ... powa 'n spikes teen ...
The different effects can be configured quite easily, I admit it must be a little time to adapt well to be comfortable with the name of the effect parameters

SOUND QUALITY

I use it for a short week with a BC Rich NJ Beast on a Marshall combo (eurkk) hybrid. No I find that the effects really make it, but I have not had time to test everything yet. The rendering of distortion is comparable to the real kind MT2 Boss pedals etc.
For simulation of preamp, I'm more mixed, there are good and bad for my taste (eg 5150). But it must be arranged by fiddling the parameters of the simulations. A check then.
I had the chance to test it for a few hours with a Jackson Dinky United States ... and there ...... no I think it's best used with a skyscraper worthy of the name (sounds NJ still very good) and especially with a good combo or stack in order to assess the best opportunities

EDIT of 10/01/06: for trying to exploit some of this multi-effects overdrive on a JCM 800, I was very disappointed, it colors the sound as not possible, either pre-or JCM in four cables, it is the big shit, the grain of the JCM is violated, and it's not a matter of adjustment ... SO: Use with caution if you do not want to lose the spirit of your amp. good ..

OVERALL OPINION

I find the value for money than convincing, I paid 430 euro in trading a lot. At that price it has everything sfaut underfoot ... for the price of 3-4 Boss pedals ...
I tried the POD XT Live, even if it's not really comparable, I prefer the GT8. Also tried the GNX4, bofbof some metal sounds on the GNX4 not bad ... too many functions that had not useful ...
I probably do it again this choice