What are you going to do with it?
IMO, the 22 MAG is a niche cartridge with a pretty limited niche. That doesn't keep it from being a useful cartridge within the scope of its niche, but only you can decide it you're going to operate within its useful range.
Also, as with any rimfire, accuracy often depends on finding ammo that makes the best groups in your rifle. With a 22 LR you can buy match grade ammo from a variety of sources, but there is no source for match grade ammo for the 22 MAG that I'm aware of, so it is more of a crap shoot.
If you want to scratch an itch and have the resources to do so, what's keeping you from buying a 22 MAG? If you buy it and decide that you don't like it, you can sell it and recoup at least a portion of your investment. You will have gained some experience and experience is seldom free.
