i personally wouldn't have a red-dot on a .22.
On a CF rifle that i needed fast sight acquisition on a larger (read human sized) target, yes and the fact that i don't need to close one eye (unity magnification) is a huge bonus in some situations.
The lack of magnification, and the lack of fine accuracy would preclude me from ever attempting a red-dot for anything but a CQB/SD weapon (shotgun/AR/Handgun).
you can get some excellent scopes designed for rimfire usage for very reasonable prices
