Things I liked: Very accurate. Easy to cock. Best deal for a sub-$40 air gun out there. It is a bit of a pain to load. A multi-shot clip would have been a good improvement to the design, IMO. But , then again, it IS only $40.
Things I would have changed: It has two potential defects that you need to be aware of. Both are easily fixable, though. One is if it won't hold pressure properly. There are two tiny adjustment nuts that work themselves loose after about 100-200 shots that need to be tightened. My guess is that the factory in China doesn't put a drop of loc-tite on the threads and the German version does or has an extra retaining screw. Look online for instructions on where this part is and consider applying a drop of the lower strength(so you can readjust it later - just don't want it creeping back out slowly is all) loc-tite on the nut(s). The other is the trigger. I've heard grease and other explanations for why this happens but the real reason is obvious with the grips removed. There are two springs that give tension on the trigger assembly. The larger one is held in place by pretty much nothing except the outer case and has a LOT of play in it. If it slips too much or if the thing works a groove in the plastic over time, it can slip enough to not cock reliably. If it doesn't fire when it is cocked, open it up fully, remove the grips and gently nudge the firing pin/valve to its fully extended position. With the cover off, it's clear that they cut corners and the stamped pieces are cheap and quite loose. So it gets a bit sideways/bent and won't work. I think a solution might be to put a shim around the screw post that the loop in the spring goes around to make it fit snugly/with no movement.
What others should know: It likes to shoot moderately heavy pellets. I got almost the same FPS out of 10-11gr pellets as 8gr ones. Super-heavy ones did lose about 100fps, though they had a definite "rainbow" arc to them. This appears to be true of pneumatics and PCP in general - use as heavy as you can be accurate with. Note: The reason why is that as a spring-piston design moves forward and compresses the air, pellet weight and resistance matters more and slows the mechanism down a little bit. It it cocked and when you fire, it slams the piston down the tube - so resistance that it is pushing against is a big factor. Pellet weight is critical in a spring-piston design, and doubly so for a single-stroke type like the IZH, FWB, or other match/competition type rifle. Often a specific gun will only "like" a couple of pellets. A pneumatic or PCP generally is more efficient as it lets the pressure go at once in a quick blast. There is no resistance on the mechanism. It lets X PSI go every time no matter if it's 5gr or 50gr. So the only real issue is friction in the barrel and being hard to aim when shooting heavier pellets with one. Pellet weight is really not a huge factor any more, which is why most competitions have moved to PCP or pneumatic designs(also the lack of recoil is a plus)
Things I liked: This works very well for airguns, and is well built. Pretty much what other people have said about it. It's cheap and works and beats open sights by 10x if you are over 30 and your eyes aren't perfect any more.
Things I would have changed: The rear eye piece needs a separate lock-down ring as it rotates quite easily. It also isn't threaded to accept a lens cover/UV filter. The AO really needs raised numbers/symbols around the outside or an internal display or something as I have to focus and then look at the lines to figure out the exact range to target. PLEASE make the thing 1/8 MOA. 1/4 MOA might be fine for firearms at 100 yards, but for airguns at 20-50 yards, it's often the case where you're caught halfway between clicks.
What others should know: Uses a standard thread 43mm UV filter - get at any camera shop. Also, the illuminated reticule should be used on the lowest setting - green for day (I find it neither good or bad), and red for night, where it won't ruin your low light vision. The red is not a gimmick and really works. At dusk/dawn or at night, you simply cannot see the cross-hair but turn on the red at the very lowest setting and you're golden.