Feature:
Has everything a decent mic pre should have: 48v Phantom power, low cut (with selectable frequency), phase invert, even a limiter. The Digital output is nice. I wish it did other frequencies besides 48kHz and 96kHz, as I don't prefer to work in either one of those - 44.1 or 88.2 is my preference. The metering looks cool, but is not very useful. It doesn't seem to reflect what I'm seeing/hearing out of the board.

Quality:
It's built very nice for the price, no doubt about that. It's good looking gear. I'm not too upset about having wall-wart power supplies. The connectors are decent quality, and the pots/knobs feel solid. In use is where the cheapness becomes apparent.

Value:
Solidly built, good looking, and the sound isn't bad - it just isn't good, and definitely not "pro" - but for the price who could really argue?

Desirability:
Well, it looked like it would be more useful than it actually has turned out to be. I'd say a lot of these have been sold on price alone, since it's rock-bottom.

Sound:
I've been testing a pair of C Valves here in my studio, since for whatever reason my church bought four of them, and hardly used them before putting them on the shelf. I got curious about why, but I think it's becoming clear...this is not even passable as pro gear, even though the 24/96 SPDIF out is a nice touch. The tube saturation is not bad sounding, but no matter how I set them I get this contrived "dry signal + tube grit", instead of a nice subtly colored sound. I've also had ground hum issues no matter what I do (ground lift, different circuits, etc). That's not acceptable in my studio! The limiter is a nice feature, and is fine if you want a hard-edged bulldozer of a limiter, but don't expect it to be subtle; It's not.

Ease of Use:
Simple and straightforward - seemingly. However, I've had difficulty finding settings that didn't give an air of "hey! I'm a cheap tube preamp!" The gain staging is a little tricky if your goal is to use the limiter, but not have it slammed the whole time.

Support:
From what I hear, Samson support is pretty good. I haven't personally used them however. I couldn't imagine calling them up and saying "hey, this C-Valve sounds like a cheap generic piece of gear" and them saying anything besides, "well, you should have known that."

Overall:
It is what it is. If not for the ground issues (which maybe there's a remedy that I haven't tried yet), these would be great for any situation where you just needed mic preamps with phantom power - like a live 2-track recording or something. Don't expect super quality sound for this price - that's just asking too much. You get what you pay for, it's been proven time and time again.

Feature:
Enough for any recording format, digital or analog.

Quality:
Well built and sounds like Avalon 90%, and rack mountable makes it more professional.

Value:
This price is the rock bottom.

Desirability:
I got it.

Sound:
Perfect no nonsense tube sound.

Ease of Use:
Easy as you see them.

Support:
Good email response from US.

Overall:
I have tried quite a couple of preamps from behringer to ART, this preamp is built like a true rack preamp like any other but the only drawback is external PSU, which a bit lumpy. Otherwise there is no reason not to try this one out.

Feature:
Great analog plus spdif outs, can be linked with another c valve to use stereo feat. and has side chain capabilities.

Quality:
Metal case, strong, rack mountable or stackable.

Value:
Unbeatable audio productg for the price give, 24bit 96kh spidf out, that alone well worth the price.

Desirability:
Good product, if I had the money I would have bought a focusrite channel strip.

Sound:
No fat broad sound or tube like boost, but clean loudness and signal path specially thru digital outs (s/pdif). I was hopping for a sweeter sound, but I can honestly say is the best one in this price range (I had own several brand names, this one is not bad, better than presonus). I think sometimes expect miracles out of a pre-amp, is just a signal booster and suppose to be transparent, it does that. There are better choices at higher price ranges.

Ease of Use:
Yes. is just knobs that are label. no complicated science.

Support:
Have never used support.

Overall:
I hope it last, can't afford to buy another one.

Quality:
Looks fantastic

Desirability:
Who cares? Can it improve the sound quality of a microphone?

Sound:
Regardless of what parameters we change there is absolutely no perceptible difference to the sound of the mic whether it is live or recorded. "Subtle" is an under-statement!

Ease of Use:
Impossible