Know this: The 22" 1600 x 1024 is the first - as in oldest of the Cinema Displays. It therefore behooves you to ask about the amount of and what type of use your seller has put it through. These damn things do actually wear out and repair parts, if you can actually find any, will cost more than you spent for the whole display. This is, of course, a good idea no matter which model it is or what era it comes from…
Of course, everybody lies when they're trying to unload their old worn out crap, but you gotta ask, at least.
Just as people will run their TV's with the brightness cranked all the way up because they've got all of the shades up and the sun is blasting into the room, they'll do the same with their monitors, never realizing that this is the cause of their repeated migraines! On the old Cinemas, this wears out the CFL lamps (there are two in the 20" and 22" and three -I think - in the 23"), and tends to cause early failure of the voltage inverter board that drives them. The first telltale sign of impending death is a purple - magenta-ish tint that develops around the edges of the screen. Especially noticeable when first turned on and the screen is all grey.
I personally have and use both a 23"and a 20" (with the 23" on a KVM) and I've collected two more 20" and another 23" for backups.
It's a whole lot easier to just keep an eye out and pick them up when they come around than to desperately search for one after yours blows up in the middle of a project.
Know this also: If you run two of these on a G4, always run the larger one from the DVI output through a DVI to ADC power brick adapter. The 23" HD especially, puts one hell of an additional strain on your Mac's PSU that can stress it to an early death also. SO, while you're keeping watch for used displays, watch for whole computers too. They're usually cheaper to buy than trying to replace just a PSU also!
Never, never drive these old displays any brighter than absolutely necessary. They'll last much longer that way.
Last tip: The best way to ship these and not break the stand when the original box is gone is to remove the damn stand first! This requires a Torx driver #T-8 which, of course, the seller doesn't have so you get a display in the post with a broken, unrepairable stand.
You prevent this by simply buying the tool and sending it to the seller yourself.
Then they can remove it (three lousy screws) and send the tool back along with the display. You then reattach the stand and and think, "Boy, I'm glad I thought of that!"