As for the comparative merits of having a fixed or variable magnification scope, it all really depends on what you intend to use it on. If it's specifically for stalking and your ground offers shots generally of a certain range, then the fixed scope may be more useful. Perhaps if you have a rifle that has to do double as a foxing tool, or a smaller calibre vermin/fox rifle, then the variable scope comes into it's own.
As for price and quality of the optics, then if your wallet and usage allows, fill your boots. But if you have to be out in all weathers, climbing over gates, knocking the rifle against stone gate posts in the dark in your efforts to save the pheasant poults from those maurading foxes, the mid priced offering would seem to fit the bill.
The point I'm making is that the best scope is the one that best fits your intended use I should say.