I don't own one so this isn't as comprehensive as you might like but its my understanding that they are reliable and there's a ton of parts available for them. You can fit one into an ar outfit, turn them into tackdrivers with thumbhole stocks and bull barrels. You can have 100 round drum magazines. They are like ARs or 1911s. No one .22 rifle shares that kind of aftermarket support.
IMHO the base gun is a decent, reliable .22, but like the others said, the real fun is the depth of the aftermarket and the ability to customize it to your taste.
Lightweight, fun, and accurate. Easily busts clay pidgeons (stationary) at 100 yards with a cheap scope. Oh, and you can change the barrel with just two allen bolts.