Thought I would jump in and give my 2 cents on my experience with Vortex. I recently purchased the Vortex Crossfire 6-24x50 (1" tube) from SWFA.COM on sale for $99 (This scope has been discontinued and is being replaced by a 30mm tube).
Mounted the scope and took it to the range, but it wasn't holding a tight zero. I called Vortex and they said that they had been having some trouble getting the workers in China to properly tighten the turrets recently. She asked me if I was planning on hunting soon. I told her "in a couple of weeks." So she said that she would FedEx overnight me a new scope that will be inspected by their tech there at the office in WI. When I got the replacement scope, all I had to do was put the old scope back in the box, affix the prepaid label and send it back. (Oh, and a free hat come with my replacement scope).
I mounted the new scope and zeroed it in...it held a sub MOA zero. Then I did a box trill and found the MOA adjustments to be very precise.
So I took it to my hunting location to get some long range shots in. At this point I had never shot a rifle over 350 yards, but I was intending to make a long range set up out of this scope on my Rem 700 7mm mag. With a muzzle velocity of 2880 (hand loaded Berger 168gr VLD's / 62 gr. IMR4831 seated against the lands) my ballistic chart told me to adjust 54 clicks up for a 700 yard shot. I put up a 3 foot cardboard target at the other end of the cut bean field hoping (but not expecting) to at least hit the target. I set up with a front rest and rear sandbag and took 4 shots. Then I drove up to the target and was suprised to find a 5.5" group just a few inches above bullseye (I chose a day with no wind so I wouldn't have to worry about windage adjustments). Very impressed for a $100 scope.
Just a few drawbacks: First, 21-24x can be a little fuzzy so I keep it on 20x and it is very sharp. Secondly, the Paralax adjustments are a little mismarked. When adjusted to perfect focus at 700 yards, the paralax marking was just at 150 yards. I assume that this is no big deal. When making the adjustment I just adjust for focus anyway (not looking at the markings).
Overall, I was very impressed. At first I thought I would have pay for something in the Viper line to get this kind of performance, but am happy with the Crossfire.