The market is moving toward striker-fired, polymer-framed pistols. It would be stupid to ignore that trend. To compete in the LEO/Government market, it's the easiest, and currently, most popular choice.
Ruger took advantage of the trend, and the developments, that Glock is just now beginning to emulate.
As to reliability, Ruger has as good a reputation as Glock. Glock, located overseas, has resisted the type of recall that Ruger, an American company cannot afford. There have been problems with firing pins, connectors, unsupported chambers, sights, and magazines with Glock. They always blamed the ammo, or the operator, while making running changes. So what?
You could say that any polymer pistol is a Glock copy, but that doesn't make it correct.