You are really going to find, as others have mentioned, that a 5.56 rate can is going to be a big weight on your .22s. I have a Kestrel 556 and that thing is a massive stainless steel anchor compared to my Guardian .22.
Now, if you can only afford one can, then go for one of the jack-of-all trades ones out now (like the Optimus or The One, or one of the several others). I've read that if you put a mag of full (high) velocity rifle rounds through a can, after shooting .22 or other pistol rounds, the heat from the full power rifle round will burn a lot of the left behind crud out. YMMV on that though.
There is something to be said for having a suppressor that is proportional to the gun that is hosting it, just from an aesthetics point of view.
And extremely high pressures.Centerfire cans stay pretty clean due to the pressure is my understanding. Someone else can further clarify.
It's only a 20 ounce suppressor, on a 17 ounce gun.You need an arm brace and you're good to go.