Ive been looking at these 2 for a 22 pistol (as well as the Buck)... It also seems like the Ruger is pretty customizable...
Regarding customization, one important thing about the Ruger is that, unlike the 22A and the Buckmark, the barreled receiver unit is the serial-numbered part and is therefore legally considered to be the firearm. If you want to swap barrels, additional units require FFL transfers for interstate purchase and sale, they can't be mailed by non-FFLs, and they may be subject to in-state registration and transfer requirements where applicable.
The Buck and the 22A are designed in such a way that the barrel can be changed without affecting the serial-numbered frame, so there are no extra legal hoops to jump through. Barrels can be bought and sold without FFL transfers and they're mailable.
One thing I forgot to mention about the 22A is that the scope rail and
sights are integral with the barrel unit; look closely at OkieCruffler's picture. The nice thing about this design is that the barrel can be swapped without having to sight it in afterwards.
Speaking of which, do you mind sharing the amount you paid for the second barrel?