I fell into Tequila Herradura when an article in Smithsonian Magazine centered on Herradura. Whether it is mid range or high end depends on your budget.
A classic bartenders' bet asks the customer to distinguish between the customer's call liquor and well liquor in two otherwise identical cocktails. The bet is usually double or nothing for the price of both drinks. The customer rarely identifies the call liquor, so if you are mixing, don't over spend.
If you are drinking straight tequila, note the difference between straight, reposado ("rested" or briefly aged) and añejo (aged.) If I am drinking straight tequila, it is almost always reposado or añejo. Tequilas labeled puro de agave or 100% agave are almost always the way to go.
The bottle on my shelf at the moment is Cazadores (Hunters) Reposado, solidly upper middle range.