I had diamondback and sold it. Got a monarch 2.5-10 never looked back. I have one viper and it's nice
Not sure what the hype about vortex is.
For the $$$. Nikon is better IMO. Rather have pro staff than crossfire or diamondback
Vortex is faster turn around time when it comes to warranty

All of them do something better than the 30-06, but none of them do everything as well.