Well... I purchased the thingy, even if I stated that they have no shame to overprice it so much, and I even take a crusade to made a 3d printed 80 bucks max on materials (the pcp kit for the crossman 2240 and a crappy barrel from Gamo) pcp, double action, 23cm pistol with small game power, that for stupid legal reasons I can't even print in my country (but I found someone that can on his) to teach them a lesson...
But finally I purchased the thingy because... I like airguns, and this is the best thing ever produced in pistol format, even if its overpriced has f***, and lucky me, I get the V1 version that is more expensive than the newer V3 versions... for some reasons.
Don't even shooted yet because I only have .177 pellets in my house and no airgun shop in my entire city, well, I dry fire it to adjust trigger sensibility, so I cant talk about accuracy or any feeding/shooting problems yet.
The good:
Best air pistol ever made, his direct competitor, the evanix Viper is eons away from it, as other patetic iterations as the Sortie, with plenty of malfunctions, and the meh Evanix Ar6 Pistol that has some problems with double action and depletes almost all the presure with 4 shots.
Internally diferent, at last! The secret of the Gk1 (and the K1) is a higher working pressure and using a valve system that is more logical and efficient than the old -lets punch really hard a rod to open more air flow- that has to travel a narrow space, with a really hard spring thats impossible to compress with a decent trigger pull, so more air wasted on reseting it, etc... etc... The firing valve on the GK1 reminds me off the system that uses the Umarex T4E series of crappy Co2 shooters, but in reverse and perfected.
Semi-auto, insane power, easy to regulate on the go (where is legal to do it).
Really lightweight!
The not so good:
The instruction manual on mine have an attached advice to not continuos rapid fire it... WTF... I will do it anyways.
The carbon fiber tank... are they suposed to have a much shorter lifespan, and have to be revised every 5 years? I don't know if its the case with the GK1, but I would rater have prefered a traditional steel tank even if it weights a little more for durability.
So much wasted space!! the grip protudes too much and increases the overall length, I thought the objective is to make an air PISTOL that could be called a pistol. I know its better to be front heavy and that helps with the recoil and control... in a firearm... But this is air, the recoil is totally controllable and you can make it front heavy anyways without increasing the overall lenght just advancing a little more the grip.
Also, the barrel ends before the endcap, so, this pistol could have been about 28cm long instead of its 32.5.
The charge rod gets in the way on left handed shooters, but I see that this is a problem solved on the newer V3 versions.
The air port is exposed to dust and dirt, just inexcusable.
The recharging method is just meh.
Trigger lenght is non adjustable and a bit too short for my taste, also come too light from factory.
The whole mechanism turns it into a always cooked and ready to fire gun. The only thing that prevents it is a small mechanism that I bet if the gun recives some hit, it may accidentally shoot. In the rifle format this isn't that big of a problem, but with a pistol that you could carry on your body to go hunting or something, on that dangerous permanent state... I don't know, maybe I'm wrong... but unless I see someone bashing his charged Gk1 on a table and the thing not firing, just seeing the whole mechanism makes me feel uneasy.
Things that can be 3d improved:
A plug to cover the charging port when you are not filling it!
Another grip that not protude out of the upper body of the gun. It will have to replace also the trigger guard and maybe the transmision rod to advance the whole trigger further.
A loading gate that don't cost 28 bucks, cause theirs is also crappy 3d printed.
Tuning gear connected on the regulator to adjust the power at any time, plus mechanical numeric indicators, it can be done... but for some reason the manual states that you must turn the valve just a quarter every time.... why? I don't see any mechanical problem with not doing it that way.
When I finish the Cheapo/poor man's Huben GK1, I will compare the two, and then maybe I'm gonna start making 3d mods for the GK1, wich I can never use on mine for legal reasons on my country.
But it’s a PITA to pull out the extension cord, extend the light stand to set up. It works. Today I disassembled the lite setup and put the
lites under the eave. 10,000 lumin for each lite. And I’m going to hardwire them into my lite switch inside by the back door. I’ll shoot way more because of the convenience. 2 catches. Don’t know if lites will stand the out doors. And has been OK’ed by the main squeeze. Any side bets?
My shooting table is behind ladder. Looking forward to using the springers with this. Crow
. This picture was taken in 2010....like to share because a lot people didn't even know they made this model which in my opinion was better than the TX 200!!!!! I had 3 TX 200 it out shoot them all at 35 yards!!! Scope was konus 6-24 when they made them in South Korea great glass!!! Tough scope too. Now they made of China 
. Also, waiting on the Crosman Two Stage Trigger, should be here in a few more days. I have the need hammer from AlchemyAirworks just waitin.