I just bought a Weihrauch HW97K last month from Krale in .177 cal. I'm limited to a 10 yd. range right now, unless I want to freeze my tail off; but I put three shots through one hole with it that you'd have to compare side-by-side with another target to recognize it wasn't just a single shot that went through it.
I've tried a half dozen different kinds of pellets through it. It likes all but one of them. Which is nice. It's not picky about what I feed it.
This is my first spring piston air rifle. I'd heard about how hold sensitive they can be. But although I've only put around 200 or so pellets through it, I haven't really noticed it being hold sensitive at all. I hope it stays that way!
I bought the 20 Joule / 14.7 Ft.Lb. model, and it seems pretty powerful. It took out a large rabbit with a body shot with no problem. I hadn't shot it enough at different ranges to be confident to go for a head shot.
Make sure you tighten the screws and check them periodically, or loc-tight them. My accuracy started suffering after a while. I quickly discovered it'd shot itself loose. I don't know if it came that way or not, but now I know to check them from time to time.
The trigger is fantastic, and overall, it's a well-built air rifle.
I'd buy it again.
I hope this helps.