Feature:
All the sound choices I need; however, one can add to the "sound library".

Desirability:
Looks really cool when it's on; the lights.

Sound:
With this amp I am able to get virtually any sound that I want, without a bunch of cumbersome pedals! I own a Mesa Boogie Dual Rectifier Road King, a Marshall JCM 2000 Dual Super Lead, as well. I now prefer to use this amp exclusively.

Ease of Use:
You have to experiment with the amp. It's an instrument unto itself and has to be learned, which is part of the fun.

Overall:
If if were lost or stolen, I'd buy another.

Feature:
Quality amp sims and lots of great effects. The only thing keeping this amp from getting a 10 here is the lack of an intelligent harmonizer. I also got the long board controller with it and can't imagine using this amp live without it. The 2 amps at once thing is really awsome, too. It can give you an incredibly thick live sound.

Quality:
After I first got the unit (had it for about 1.5 years now), the amp froze on me. I called Line 6 and they told me how to reset it. The problem then was that it reverted back to the original settings so my custom patches were all lost. I've since backed up all of my custom patches on my computer in case it happens again (which it hasn't).

Value:
For all that you get here, the price isn't bad at all. Not only do you get the best amp sims made, you also get all these professional quality effects. Add in the other little things (like the quality of the direct outs) and this thing should probably get a 10 here. But hey, I'd always prefer to pay less.

Desirability:
This is really a BS thing to rate so I'll just give it a 10 since it's one kick ass product regardless.

Sound:
This is as good as it gets for an amp that simulates tubes. Is it as good as a Mesa Road King II? No. But this amp is fantastic for playing gigs. I've done some recording with it, but prefer using real tubes for that.

Ease of Use:
I really had no problem getting control of this amp and finding great sounds. I give it an 8 because I know many people who have had trouble with it. But I think if you're of average intelligence and can use a computer, you can use this with no real hangups.

Support:
These guys were really great at helping me on the one occasion that I needed help. Line 6 also has some great message boards to get info, as well as a place on their website where musicians can go to upload their custom patches or to download the custom patches of others.

Overall:
This is my live amp now. I play in 3 bands (metal, jazz, and classic rock) and this amp's versatility makes it great for all of them. I can have a killer Mesa rectifier sound or a classic Marshall tone. But things really get crazy when you mix the two together (amp can simulate two amps at once). This is probably the best musical purchase I've made in the last 10 years (and I've probably spent upwards of $70,000 on gear in the last 10 years).