I really like a lot of the Diamondback line, as far as value for the money. But I'm not sure I'd recommend the spotter for anything outside of a range spotter. That said, you find Vipers on sale or refurbished for pretty close to the Diamondback range, I paid something like $500 for my Viper 15-45x65mm on sale. Or, and as a Vortex fan that is physically painful to admit, possibly look at the other options like mentioned by Doug over at CL.
Personally, I run the Viper, and I'm pretty happy with it. But ya, I don't think you will be happy with the Diamondback for serious in the field work where your trying to decide if it's worth the hike to try and get a shot. Now if that isn't what you need them for, IE you just need a range scope, then you should be fine with a Diamondback. But if I had the choice, I'd find a used first gen Razor or try and snag a deal on the Viper. It can be done, will just require more shopping. But I know its a hard call when the budget is limited and you really like the Vortex stuff, you can find some really good deals on the Diamondback line. Plus, the beauty of buying used Vortex, its no risk. If you buy one that has a problem, Vortex will fix it.