Feature:
It's a 4-channel mixer. If you've looked at the pictures, its pretty basic. 4 inputs, 4 volumes, 1 output.

Quality:
Extremely sturdy casing, REAL METAL, not that BS plastic crap. As stated in another review, the knobs would be the first to go, but I opened it up and looked at the circuitboard...they're pretty well anchored in there.

Value:
I have a USB interface for recording, and I bought this for drum mics, and it really does what I bought it for. Once you get up above 5 channels, the prices skyrocket with added features that I'd never need (thanks to Adobe Audition), so this is precisely what I looked for.

Desirability:
Rugged, streamline, simple. It's not as big as it looks. its about the size of 2 cell phones stacked on top of each other, so people who like compact devices, get one. Oh, and...this thing is SEXAAAY!

Sound:
For the price (and size), this little contraption has god-like sound quality.

Ease of Use:
Plug and Go...how much easier does it get?

Support:
Our bassist has a Behringer Bass Amp, and that thing (literally) rattles the house we play in. Behringer is one of the few companies that make legitimately quality products for the right price. Good Job Behringer!

Overall:
Reliable, consistent functionality for cheap. Isn't that what business competition is all about? It might not have built-in EQ or effects or all those, but I do that on our band's PC, so all I needed was something to mix the drums right without having to record 4 separate tracks. If all you need is something small to say, bring a singer's voice over a screamer's, and into only one PA Amp, this would work. $30 is pretty much a bargain for this, I've seen 2-channel mixers over 5x the price, and they're bulkier too. So if you just need a simple mixing solution, this is the way to go.

Feature:
Not many features - four volume knobs, that's pretty much it! But that's exactly what I wanted.

Quality:
Rugged case gives me no worries. I suppose the knobs might break if I abused this little box, but I'm not worried about tossing it into a case with foot pedals and the like.

Value:
Outstanding value. Just as simple as I want, for a VERY reasonable price.

Sound:
Clean, accurate, transparent... all the things you want in a mixer.

Ease of Use:
Good knob design makes the settings easily visible, and smooth controls makes this a simple and easy mixer

Support:
(no experience)

Feature:
Being abble to control the volume of each input device, allows me to control which device to have "on top". At times the radar detector "reports" the presence of McDonalds or a Micro Wave tower. The Micro Wave tower can cause the radar detector to go off for minutes at a time and it can be truned down while maintaining the music at appropricat levels.

Quality:
The device seems indistructable. I went on an 11,000 mile trip and the MX 400 never gave me a problem. I whish I could say the same about the devices I connected to the MX 400.

Value:
I have seen other multi imput single output devices used by Motorcyclists that cost 5 times as much and only had one main volume control.

Sound:
I am a motorcyclist. I have three imput devices that I need to listen to through one set of ear buds. The imput is from a radar detector, xm radio, and cb radio. I do not have nor need a gps, but if I did, I could listen to it through the MX 400. The quality of the music from the xm reciever is excellent.

Ease of Use:
Plug the devices in and go.

Support:
Haven't needed any.

Overall:
I will never regret the purchase of the MX 400 and continue to use it to listen to FM radio and the radar detector at the same time.