For mixing I really like Hornitos. I haven't investigated tequila as a sipping drink, though.\
There are generally cheap but high quality versions of all spirits because a lot of the price (this is especially true for, say, whiskey and vodka) is marketing. The best gin cocktail I've ever had was made with Gordon's. I'd probably never sip Gordon's, but that's typically what I stock my cabinet with unless something fancier's on sale.
For whiskey, it's a bit of a dirty secret that a handful of distilleries do all the distilling for the whiskey industry. The only difference between them is the time, type of barrel, and of course, the marketing. Alberta Distillers, for example, does the distilling for Canadian Club (I think, either that or Crown Royal), and you can get AD products for a serious discount.