I've used my Viper 6.5-20 X 44 at 300m and 500m at the KTSA ranges in F class, and look forward to trying it out at 900m. As it's my first scope, I can't compare it to others, and obviously there are better scopes out there, but for the money, it's a damn good scope with an unbeatable warranty.
I'm definately on a budget, and this scope fit my wallet quite nicely. I chose the dead hold BDC reticle, and it works well for me. I would not recommend the target dot reticle: the cross hairs are nice and fine, but the dot is too large and obscured the target.
Since the changeover to the ICFRA targets, the v-bull is getting hard to see, so I've been putting the v-bull in the upper right quadrant of the cross hairs. It seems to be working.
You can check out your reticle choices at the Vortex site. Oh, and welcome to F-Class!