Feature:
It would be nice if there was more choice of compression ratio (the only choice is between compressor and limiter). But for just about all purposes this is all you need, and when you factor in what you DO get for just over a hundred dollars, this should not even be a concern.

Quality:
How can I judge this fairly? Because, like others here, my unit did not work when I got it. I had virtually no ourput at all. Maybe a loose tube or something, but it seems to happen to a lot of people. But Zzounds was extremely helpful with the RMA and I had a new one in a couple of days, which they shipped up front before I sent my defective unit back. Which I thought was very very cool! As for the unit that I have now, it is very solid and feels satisfyingly hefty for a small box. But I had to deduct some points here because of that first one. When I called ART to ask about the lack of signal coming from it, they were very helpful and got right to the heart of the matter. They seem to be a great company, I would only add that since I saw a few people here saying that the first unit was defective that ART steps up the quality control a little bit. It probably was just a loose tube, and the others here may have had the same problem, but if the tubes are coming loose during transit then they might want to look at some sort of a brace over the tubes to keep them securely in place.

Value:
This category should go to eleven!

Desirability:
The fact that for just over one hundred dollars I can get a very sweet sounding tube preamp/compressor with hand matched tubes that could fool people into beleieving that it costs ten times more than what it does makes the Tube PAC very sexy to me!

Sound:
Sounds great and is totally SILENT when not passing signals along. Therefore it works perfectly for getting those "clean but rough around the edges" guitar tones that can be so frustratingly hard to get. Think Link Wray's "Rumble" and you are in the ballpark. And it's also the sound that gives developers of virtual amp software fits trying to emulate. My other planned use for it is as a mic preamp, but I have not used it as one yet. From what I tell with the guitar I think that it will be very nice. I also plan on a couple of less common uses, such as putting it between my synth and an amp.

Ease of Use:
It's pretty much self explanatory. But you will need to hit the manual to find out about the two step ratio deal for the compressor/limiter.

Support:
What can I say? They answered the phone right away, they actually listened to me, and they got to the heart of the matter quickly. The whole call, from dialing to getting my answer and hanging up was under two minutes.

Overall:
I ilke everything about it so far!

Feature:
Would have liked more flexibility in the compressor section, but it does alright with the "pre-sets"...

Quality:
I don't know here. The first one I got worked 5 minutes, then crapped out. I got a replacement, and in the meantime fiddled with the first one. Took it apart, pulled out the tubes, put them back, and now it works fine. I guess maybe the tubes weren't seated well in their sockets? We'll never know, but it works fine now.

Value:
Seems like a nice sounding unit for the price, especially noting the various uses I've found for these.

Desirability:
Its just something I needed, gets the job done, nothing more!

Sound:
This sounds pretty nice. Warmer and fatter than my DMP3 or Mackie pre's. I mainly got it as a bass DI for recording, then found it sounds nice with an AT2020 mic for vocals, and nice as an acoustic guitar pre for live use.

Ease of Use:
Super easy...plug it in and go. Again, it would have been better if the comp had more adjustability, but the settings it has make it kind of a no-brainer!

Support:
Don't know, never tried them!

Overall:
For the money, nice. I've got the two now, and don't plan on getting rid of them anytime soon. They work, they sound good, and until I can kick $2000 for something REALLY Nice, I'll keep working with these.