The full size was made by Walther but has been discontinued - it’s not the same quality as a SW MP 9. But you might get lucky finding one languishing for sale at some LGS if that’s what you want. The compact is actually made by someone else (probably umarex) but I don’t have one so I won’t comment on it.
I got the full size because at the time it was the only full size .22 that approximated a duty pistol, aside from a $500 conversion kit. Now glock and others make these .22 pistols. I’ve put thousands and thousands of rounds through mine, mostly suppressed. It gets dirty quick, and becomes unreliable when dirty. The longer I have had it the fewer rounds it can take between cleanings before being unreliable. Currently I have to rack the slide about once a mag and it gets old fast — Even if I just cleaned and lubed the rails. I have to give it a blast with a garden hose and a detail clean to get all the gunk out, if that doesn’t work I’ll likely get a new suppressor host. At the end of the day, these are pot metal pistols made to profitably be sold for $2?? - so I don’t expect them to last forever. Indeed I can see an awful lot if wear on the internals of mine. If I were getting a new one today, I’d look at the new Taurus .22 (can’t remember the model no) but a buddy of mine has one and it looks really solid compared to the full size M&P. It works reliably and includes the threaded barrel and everything else for suppressed shooting. For pure suppressed plinking I’d get the Kel-Tec .22 with the huge mag and top rail (again can’t remember model no). If I wanted a .22 that lasts forever I’d get an old woodsman or a wheel gun. Good luck.