The U.S. Army did use the Redfield scopes in Vietnam. I recently picked up an old gloss 3-9x40 steel tube for $20 in a small town gun store and it is so clear. They were very rugged. They still bring $100 to $200 here in the USA. Back in the mid 1990s, they made a 4-12x50mm, the Illuminator, which is very sharp. A friend, a retired gunsmith, former U.S. Armory armorer, and later a policeman outfitting SWAT teams, has one on his Model 70 .30-06, and I have seen him shoot 5 shot groups of a cloverleaf at 200 yards, which is good for a hunting scope.
The current Battlezone model is pretty sharp, and has a nice G2 reticle, for under $200 here.
With any optics, you need to look through them, not just in the store, and try them in the field. Talk to owners about durability. If someone is using a scope for 15, 20, 25 years, it must be pretty good. If they work for you, and you can tell little difference or no difference in your usage between one glass and another costing multiples of it, they listen to your own eyes and wallet.