I have several Ruger's and Buckmark's. Ruger Mark I's, II's, and Mark III's are a total PITA to disassemble and reassemble. No way around it. There are aftermarket companies who offer different pawls and other such parts that help in getting the damn things back together. But they're still a pain. You have to be really familiar with these guns, and know all of the little, "tricks and secrets", or else you'll have a difficult time. The problem is 99.9% of the buyers of these guns don't. Overall you'll have a more difficult time putting a Mark I, II, or III back together, than a whore trying to keep her skirt clean on a dirt floor.
The Mark IV is a whole different ball game. They are a breeze to field strip and reassemble. Much easier than the Buckmark, because there are no screws or tools involved. So as far as breaking all of them down for cleaning, installing aftermarket parts, etc. The Ruger Mark I, II, and III are a PITA. Then comes the Buckmark. And the Ruger Mark IV is the easiest of all.
The next difference is the Ruger is all steel, (except for the frame on the blued Mark IV, which is Aluminum). The Buckmark employs an all Aluminum frame on all of their models. This is personal preference, because both the Aluminum framed Buckmarks, and steel framed Rugers run fine, and deliver years of shooting, and tens of thousands of trouble free rounds.
As far as price, there isn't enough difference to worry about. The same can be said for different styles, types, and barrel lengths. Both have something to suit most everyone. And most importantly from a suppressor standpoint, both offer many threaded barrel options. As do aftermarket companies, which are well supported by both models. And as Tom said, other then Ruger and Browning, there really aren't any other manufacturers worth considering in a suppressed .22 pistol.