The Vortex Crossfire is the lower end Vortex model that's their only scope made in China. I've read several good reports about them, but then I've also read several reports of guys having problems. Vortex did take care of them immediately, but you still don't want to have the problem in the first place. It's enough that I'd probably not buy a Crossfire unless I was on a super tight budget.
The Viper is the next step up from the Diamondback. It would be my choice, and since they are on clearance right now they are the best buy imo.