I am one of those people who actually own one - along with 10 AR's in various configurations and a Ceiner conversion kit.
In terms of accuracy it is better than a Ceiner conversion and about par with most box stock 22 semi-autos like a skinny barrelled 10/22 (10 shot groups that can be covered with a nickle at 25 yards).
Reliability was hit and miss for about 150 rounds until it was broken in - it has been relentlessly reliable since then and eats just about anything in terms of .22LR ammunition.
It has an adjustment screw behind the recoil spring so it can be adjusted to work with subsonic, std velcoity or high velocity ammunition. I suspect some of the "it does not work well" comments are from 'tards that have taken it apart and not understood that where the adjustment screw is at is important. It's covered in the manual but you have to be able to read to benefit from that.
The durability is in my opinion head and shoulders above the GSG .22. The main objection people seem to have is the pot metal used to contain the bolt assembly in the upper receiver. Yes it is pot metal, but when you look at it and actually think about it, it is more than up to the task. It lies inside the upper so it is well protected and unstressed, and it performs exactly the same function as the cheap and comparatively flimsy stamped metal rails used in the Ceiner conversion and all of the derivatives of that design. From that perspective the pot metal carrier is overbuilt. The halves of the carrier are also bolted together with separate captured nuts and bolts so stripping them is a non issue and none of them are going to come out when the rifle is in use. It is in short a solid and well designed approach to a .22 LR system in a AR clone upper.
The trigger is a bit gritty but serviceable andon par with a service grade AR. I am also confident that an aftermarket trigger will come along to resolve any potential beef there. But as is, it does what it is supposed to do and is not innappropriate for field use.
The only significant negative from an AR procedures standpoint is the lack of a functional slide release. (The forward assist is also non functional, but that is no big deal.) Otherwise the rifle handles well and feels like an M4. One oddity is the safe/fire switch runs through 180 degrees, not 90 as is the case on civlian AR's. A positive is that the barrel starts a bit back from where the barrel extension would end, so it manages to stuff an actual 16" barrel in a 14.5" package as the barrel essentially runs through an smooth bore M4 shaped "barrel".
The only other negative are the 30 round magazines that are about 5 rounds too long. If they came in a 25 round model the same lenght as a 30 round AR magazine, I'd be a happy camper. But on the other hand, the mags are super simple and super fast to load compared to the black dog mags for the Ceiner and similar conversions. Again, I suspect someone will come long with a shorter mag, so I would not pass on the rifle because of that.