I will throw in my 2 cents. I will speak from personal experience of 1000's of rounds as I own or have owned the Browning Buckmark, Ruger Mark IV, Beretta U22, GSG 1911, Sig Mosquito, Smith and Wesson M&P22 and the Grand Power K22 X-Trim.
As for reliability of cycling I would rate them as follows:
1) toss up between the Mark IV and the Buckmark. They both eat ANY ammo. Rem gold, fed blue box, wildcat, blazer, etc. Some guns are very ammo sensitive. Of my experience, these 2 boggle my mind wrt as to how reliable they are.
2) S&W MandP22 and the Beretta U22 - almost as reliable as the buckmark and ruger mark iv with the same garbage ammo. Both just cycle. Period.
3) Grand Power K22 - very reliable but not quite as reliable as the others on the garbage ammo. Might get 1 or 2 FTF or FTE every 100 rounds.
4) GSG 1911 - runs great with mini mags and cci blazer. Will run on the cheaper high velocity stuff but expect to be dealing with jams on a more regular basis. Great gun for the $.
5) Sig Mosquito - avoid.
As far as what one I would buy, I would recommend the following ranked highest first:
Buckmark - This is my favorite pistol for just straight up fun and accurate plinking. It fits my hand (UFX Camper model..cheapest one they make) like a glove and it just overall feels like quality. Nice adjustable sights. One of the best deals going as far as target style 22's imho. I picked mine up for 360$ last year but they have gone up a bit since. The trigger is phenomenal..right up there with the K22 trigger. I will never sell mine. 1000's of rounds and it still runs like a champ.
Ruger Mark IV - Very solid and accurate pistol. Hands down the easiest to service with a tool less 5 second field strip. The trigger is a bit heavy for my liking but it is very solid and predictable with very little to no creep. Like the buckmark, it is heavy which i really like in a target pistol. Not as comfy in my hand when compared to the buckmark but different pistols fit everybody differently. Nice adjustable sights (target version) and the mags are very nice aswell. Cleaning is the easiest of the lot.
Beretta U22 - This is one of the more under rated target 22's imho. I sold mine to finance another project but it was a fantastic gun with the nicest mags of all of them. Runs on any ammo. Very accurate 6 inch barrel with nice adjustable sights. The grip was a bit on the small side for me (i have large hands) but it fit me well. My only real complaint would be the trigger as it was a bit stiff and somewhat gritty with a noticeable bit of creep. Other than that, it is a great pistol but for the $, I prefer the buckmark or mark IV.
SW M&P22 - Kind of hard to compare this to the above pistols as it is was not designed as a heavy target style gun....but as far as function and form, it is a fantastic little gun. I agree with the NutnFancy review as I have had the same positive experiences with mine. Eats any ammo, all day long. I actually ran 350 rounds of CCI Blazer through it tonight with 3 FTF's on the first round of the mag. Very minor issue. If you are more looking for a service style gun that more matches your SR9, this would be my pick. Adjustable sights with a nice trigger but it is a little bit creepy...but still very predictable and not too stiff. Very easy tear down. Great value.
Grand Power K22 X-Trim - If value is your main concern I would pick something else as it is somewhat pricey but if you want a kick ass service style gun, this thing is awesome. Many of the same great qualities as the MandP 22 but the trigger is way way better and the fiber optic front/adjustable rear sights are the best of all of the lot. The slide is buttery smooth and it looks fantastic. Runs very well on the majority of high velocity ammo but it does have a bit of a tendency for FTF's with some of the junky ammo. Not a huge fan of the plastic mags but they work well. Wickedly accurate. I can shoot is almost as good as my Buckmark but it is not a target style 22 like the buckmark. Reliability does start to suffer around the 350 to 400 round mark but run a snake through the bore and wipe the chamber its good to go.
GSG 1911 - for 400$ is has to be one of the best values of the lot. Runs well on mini mags and other decent high velocity ammo but mine doesn't like the junky stuff at all. The weight is up there but nowhere near as heavy as the Norinco 1911 in 45. My only beef with the gun is the non adjustable sights. (yes they are technically adjustable) Swapping out the front sight and moving it around is a pain. I am spoiled from having true adjustable rear sights on my other pistols. Heavy trigger but fine once you get used to it. Mags are very solid.
Sig Mosquito - If you want a finicky gun that needs high quality high velocity ammo and has a very heavy single action trigger, get the mosquito. I could not shoot it very accurately at all. It looks cool and seems to be built solid but I would not recommend it at all...unless you are looking for a P226 style trainer or a project tinker type gun. I only put about 500 rounds through mine and sold it.
I too was in the same situation as you are now...love to shoot the 9mm from my 92FS (first pistol) but its hard on the bank account and if you are like me, I like to shoot alot (300 rounds plus) when I hit the range. For 6 cents a round versus 30 cents a round, I always end up shooting my 22's 95% of the time. Whatever you do I would recommend getting something with adjustable sights and something that fits your hand well.