Get a mid-range METRIC set from your trusted hardware store. Those are the best value in the long term as the quality difference between them and the all-out brand names like Stanley Proto & Snap-on isn't that big, though prices can be! Bondhus which is commonly available in the US is a quality brand without a high price. Just get the chrome vanadium ones if you can, they are easier to take care of in terms of rusting.
Just for reference, I have a set of 'Eight' brand, Japan made metric allen keys which I have used for 20years. They cost me equivalent of US$20/- back then and they are still in excellent condition even today!
Sorry but your vision is bit flawed. I will try to explain.
In your vision is missed what the price diff is between mid range and high end hex tools.
You assume its huge and so you come to a vision that the best value in the long term are mid range hex tools. WRONG.
The price difference is not that big.
I buy in my country a PB Swiss Tools Hex Set with balldriver + extended length, for 38,50 ( a special offer for 2014)
The best fit with lifetime warranty.
A mid range tool doesnt has the most right fit and or not the most right fit over extended time.
I admit when using a hex tool you often dont need to have the best fit, but occasionally you need.
A high end tool Always deliver, but a midrange not. On the "moment suprême" it fails.
With prices similar I bring in here, your recommendation doesnt make sense Imo.