Quoted:
Dad has a 4.5x10x50 VX11on his 338WM that has been through hell and done fine.
I have a 3x9x50 VX11 on my 45/70 that has been through the same.
They have taken a pounding in the boats and snogos.
We went with the 50mm objectives because the moose tend to come out towards dark and with us wearing glasses we needed all the help we could get.
50mm do let a lot of light in, but they are bulky. I spend most of my time hunting either horseback or on
foot so every bit I can shave off on width (try riding with a big rifle and scope under your leg) and weight tends to get shaved off.
If a hunter is doing more motorized or doesn't mind the extra the little bit of extra bulk they're a great option.
When my older sister bought her last scope I talked her into a 50mm Nikon, she loves it. Nikon's Buckmaster (mid grade series) seem just a little bit brighter to me than the Leupold VXII's and about the same as a VXIII for less money. Both companies make a good product, but for a tough scope without springing for a Nightforce Leupold seems to be where it's at.