Heres another one I have thats been very reliable, and a lot of fun. Its a Taurus POLY PLY-22. Its NOT the Taurus PT-22. Its a Tip-up like the Beretta. I have both, the Taurus, and the Beretta, and the Taurus has been very reliable, better than my Beretta, holds an extra round, has better sights, and when I bought mine, was almost $100 cheaper than the Beretta...
This next one is just on the edge of "pocketability" but is worth mention. Its the Bersa Thunder 22. Its construction is fairly unique, its one of the very few 22 pistols that has a steel slide, making it very durable. It has a nice Double Action trigger and also has been very reliable. You can find older versions listed as the FireStorm 22
This last one is the New Walther/Umarex PPK/S Replica. Its Zamac constructed, which is a Zinc alloy. Zinc has been used for many years for cheap "Saturday Night Special" type pistols, and has a bad reputation for low quality. IF engineered correctly, a pistol made from Zamac can last a very long time. There are quite a few current pistols that have Zamac construction, and they have good reliability, and longevity. The Sig Mosquito, Walther P22, GSG/Sig 1911-22 & Colt/Walther 1911-22 are all Zamac pistols, and reports are favorable as far as durability.
This new PPK/S Replica has an UNUSABLE Double Action trigger pull, but does have a very nice Single Action pull, and a very nice hammer spur, so since its just a plinker for me, I just cock the hammer for the first shot. It has been 100% reliable with almost 3,000 rounds, and I see no signs of wear. Some owners of the Black pistols have commented that the finish is fragile, but mine is nickle, and the finish seems durable enough.
There is a new version of this pistol, the Walther PPK/S COMPACT. It has a 7 round magazine, as opposed to the 10 shot magazine mine has. I havent seen this pistol yet, but it seems to have the same slide length, but a shorter grip. That would make it fit the pocket a little better.