I have the Mark 6 1X6, and I'm using the Bushnell ERS, the Bushnell has come a looong way, since the 10X40. My next scope will be the Leupold 3X18, just because I'm impressed with the 1X6. If you need some "hands on" PM Gadget he is an "end user". The 1X6 sits on a Colt 901 and the Bushnell is on a Stiller action set up for long range. The price may have something to do with it? in the US the price point is about the same, but here there is a bit of a difference.
Just to add the 3X18 is one of the lightest scopes out there, more so than the Vortex etc. For some "end users" that's huge.