So now that I've owned both, I thought I'd share my thoughts.
Setup and FeaturesThe EVO brace is ready to go right out of the box. Feature wise, it's pretty basic. I wish it would have had some QD sling points, but it looks like Midwest Industries is coming out with an adapter to do that.
My Tailhook is set up on a CZ factory cheek rest and a home made 3D printed adapter. I have the adapter set up to give me a 13 1/4" length of pull, which places the brace just ahead of elbow and positions the cheek rest ideally for me when shouldering. I also have a CZ AR pistol tube adapter, but I was able to get my 3D printed adapter working and didn't use it.
It has a QD point nicely integrated, which is good.
Note that every adapter design I've seen so far uses the factory roll pin to secure in place on the cheek rest, preventing a quick change to the stock component and adding stability. I don't know where the ATF will end up long term, but I would bet that unless they reverse themselves again this setup will be good to go. But I'm no lawyer...
Build QualityThe SBT EVO brace is very well built. Molding is excellent and the folding mechanism locks up like a bank vault.
The Tailhook is similarly very well machined. Mine had very few tooling marks, and the finish is even and durable. The factory CZ donor stock needed some work to get the hinge mechanism to deploy smoothly. I had to take out the release button and cake the area with gun grease like my EVO brace did from the factory.
Brace FunctionalityThe SBT brace concept was designed for disabled shooters, and it shows. When properly secured it's very stable shooting one handed. The problem is that it is very awkward and slow to get into position.
The Tailhook far better for quick deployment and getting into position. You can flick the support down in a second and get right to shooting. It also allows more flexibility for shooting from awkward positions. Personally, I like this much better as I have the arm strength and dexterity to not need the extra support. Frankly, the Tailhook is so simple and straightforward it's brilliant.
ShoulderabilityThe SBT EVO is very easily shouldered, and it had an identical 13 1/4" length of pull. I found that the sharp corners of the end of the brace portion dug into my shoulder during shooting. Not enough to be painful, but not like an actual stock, either. When shouldered, the brace is very stable and I didn't feel any play in the setup. The brace straps tended to scratch my cheek and snag on my shoulder a bit which was more of a mild annoyance than a real problem. I left them in place at all times to prevent redesigning the brace.
The Tailhook is even better, using the ergonomics of the factory cheek rest and providing a larger surface area and softer edges to the shoulder. It's stout and robust. I also like that it's very low profile and doesn't seem to get in the way when shouldered like the tail end of the EVO brace did. I'd say the combination of the CZ cheek rest and the Tailhook is much more shoulderable than the SBT EVO, although neither compares to the full CZ factory stock.
I did notice a bit of flex and play in the Tailhook set up as compared to the SBT brace, but I think that's due more to my adapter then due to the Tailhook. All in all it's better than your average AR15 collapsible stock, but not as solid as the 1 piece EVO brace. The adapter shown is an early prototype. I'm going to print the final version this week and I'll see if that improves things.
AestheticsThis is a matter of personal preference. I think both are handsome solutions, but I think the CZ cheek rest/Tailhook looks the best and most integrated, as would be expected.
CostThis is obviously a wild card, but I would expect one day the EVO brace will fall between $175-$225 on the street, with GHW quoting in the mid $200s for the Tailhook setup from their shop. The advantage of the Tailhook for me is that I now have the full CZ stock (I've shipped the actual stock portion away to avoid running afoul of the rules) so when I form 1 the gun I'll have already made that investment.
Still, unless the Tailhook comes down in price it'll be the more expensive solution. I think it's worth it. When we finally get factory adapters, I think it'll be even better.
OverallOverall, my pick is the Tailhook. It's a better brace for my needs, it's more shoulderable and it looks better on my setup. I like that it has a QD mount and I like the ergonomics of the CZ factory cheek rest. I think GHW has really hit on something here and I think this concept is the future of braces for the general population. Hopefully they can get factory adapters ready soon and start offering a turnkey solution.
The SBT EVO, if you can find one, is the plug-and-play solution. It just works. If they can make them in quantity it'll continue to sell well.
Final ThoughtsTo be clear, I haven't shot the Scorpion with the Tailhook installed but I think it's going to work really well under live fire.
My original intent with my Scorpion was to SBR it and use the factory stock. While that's still on the table my enthusiasm for the process is pretty low now that I have an excellent brace setup on my gun. I'm going to hold off converting my pistol into an SBR to see how wait times pan out and how the legalities of the ATF's decision on shouldering braced pistols comes to reality. This solution is so good and so versatile, I don't think there's a rush.