I've used Opticsplanet without any issues. However, I've read lots of complaints of people saying they list stuff as instock online and don't have it stock when you order it. It's always best to call ahead to make sure they have it instock before ordering.

SWFA.com is also a good place for a scope.

Cameralandny.com and Liberty Optics are two other places that might be worth checking out if they carry a brand you want.