IMHO a lot is down to the individual shooters eyesight. Dean shoots superbly with the Sightron but i can't get on with them. Pete Dutton shoots superbly with the Leup but i can't get on with them....the same with Hawkes,lightstreams and almost every other HFT style scope out there. trust me, i've tried them all bar the expensive March/NF. I've looked through the expensive March but unless you've shot it for a season you just won't be able to find out whether i suits the shooter or not. Time on the zero range just won't throw up the same parameters that you'll find on a comp course.
That's why i personally think that finding a good HFT scope is harder than finding a good FT scope as it seems to boil down to the scope vs shooters eyesight combination due to having a fixed Px. I love the 10x44 MTC Viper and keep coming back to it despite having tried almost every HFT style scope there is, although some don't get on with them. I would suspect though that due to price/ret the 10x44 is the most widely used HFT scope.