I also own one. It really is a great shotgun, as long that you take a Gen4 (Which should be the easiest one to find). I would say that since it's since it's a bullpup shotgun with a pretty short length and all, it take just a little practice to pump it correctly and avoid short strokes, which would be the most common error i have seen witht these. Pump it nice and firmly (Hehe ( ͡° ͜ʖ ͡°) ) and you shouldn't have issues.
Another tip: You can easily deactivate and activate the spring assistance of the pump action. Test both with and without and choose which one you like the most. But i prefer by a very large margin without the spring.
Biggest flaw is the loading process. It's long and take quite a few steps. But once you're loaded, you have 15 rounds at your disposal in two tubes in a small and light package.