I have a Vortex 4-16 HST that's probably 6 years old. The clicks on it's turret are more noticeable and it's harder to turn. Not a bad thing in my view. The Leupolds I have, a couple VX3 4.5-14x and three VX-6 3-18x44's are all very reliable, the clicks just feel a bit more mushy for lack of a better term. No issues with either. I like that the VX-6 have a cover for the turret, it makes me 100% certain that my turret isn't being moved unless I remove the cap and do it. I like having the option of dialing, but don't have to do it that often when hunting. I carry my rifle in an Eberlestock scabbard a lot and always worry about the turret getting inadvertently dialed even though its never happened.
The glass in the VX-6 is definitely far better than the Vortex or VX-3. The low light performance is every bit as good as the 1" tube 3.5-18x44 Swaro Z5 I have.