Well, it will mostly depend on how it sounds and since few of us have used it (me included), it's hard to reach any definitive conclusion. Still, looking at the published features, here are some thoughts:
Good
1. 3-band eq with sweepable mid
2. tuner
3. mute
4. dual source capable (any dual combination of UST, SBT, mag or internal mic)
Not So Good
1. 4 AA batteries with only 24 hours of life (you'll pay for the preamp again within a year or two just in battery costs). Apparently, there's a way to attach external power. Dunno how.
2. Lack of separate eq before blending. That's fatal for an dual source using an internal mic.
3. Lack of specs. I couldn't find any specs published. Perhaps they're on the site, or will be shortly. Maybe never.
The Tube
The addition of a 12AU7 tube running at 3 volts (through only one side of the dual triode tube), along with a "tube blend" control tells me this is a starved plate design (at 3v perhaps the most starved of all) with the tube in a sidechain (it's not in the true audio path). It's there to do one thing - to add distortion to the signal, which isn't necessarily a bad thing, but still it's only adding distortion.
Starved plate tube preamps have been around for years. They have become popular with beginning home recordists, although their popularity has waned as folks have learned that there is a night and day difference between a starved plate design and a real tube preamp. Plus there is absolutely nothing wrong with solid state preamps. Indeed, many folks have replaced their cheap starved plate tube preamps with solid state ones, and like the change.
A real tube preamp runs at 200v to 300v on the rails. There are few inexpensive ones (under $400 per channel), but most are expensive (over $1,000 per channel). The good ones are sensual, euphonic and sound incredible. Here's an example of one of the good ones:
Pendulum Tube Preamp and DI
Now, I'm not trying to compare Tak's Cool Tube Preamp with Pendulum's Tube Preamp. That would not be fair at all. But I do refer you to the Pendulum to stress my original "tube" point - the starved plate design is a gimic.
BTW: If you watch the video on the Tak site about the Cool Tube Preamp you'll notice that when the tube or magnetic pickup is blended in the volume increases. That's another marketing gimic -
make it louder and most will think it sounds better.
That all being said, the preamp overall might sound pretty good, and may eclipse other barn door units out there, which shouldn't be too hard to do.