I have two to offer comparative thoughts on, both in .22 caliber: a Huben K1 and a Western Airguns Sidewinder.
Of the two, I think the Huben has the better build quality, and is quieter even at higher power levels than the Sidewinder, even after upgrading to a better moderator, and has much better parts support (Kelly at KRAZCool provides great service, and all parts can be purchased if you want them - I have the spares I need for my Huben on hand, but can't get anything for the Sidewinder yet, not even a parts diagram). But the Sidewinder does have some great things going for it too: the removable magazines are nice (a great way to show the gun is clear if you take it to a range), a valved swappable bottle (lets you buy and bring an extra on a hunt, rather than a much larger tank), has a second safety switch near the trigger (something I really wish the Huben had), and simpler barrel removal if ever needed to clear a jamb or to clean.
Interestingly, for me I find reloading the Sidewinder mags out the gun to be no real time savings over the fixed mag of the Huben. But being able to have two or three loaded and ready to go is nice in its own way - but in either gun you can shoot faster than you can load, so that bites you either way.
If I could have only one of the two, for my use / needs / preferences, it would be the Huben - but I can see the case for the Sidewinder if you spend a lot of time in the field (using multiple bottles) or at the range (with the removable mag). Bottom line, if you only get one of them you'd love either one - it's only when you live with both that you see the differences.
That said, that Steyr is awesome! I may end up trying one someday . . .