Depending what you're looking for it can go either way.
I've bought tires via local independent shops, costco, online (discount tires direct & tirerack), and quasi-online ordering through website and picking up in store (sears) depending who had the best sale/options going on.
Buying in person you can check the date codes on the tire to see manufacture week and year. This is more important if buying a discount or odd size tire, since warehouses typically hold tires up to 5 years old.
I've refused tires at an independent dealer before for being too old.. many times those warehouses don't store them the way collectors do who drive on old tires. Rubber dries out, belt issues, etc... no old tires for me at the price they cost these days.
Costco is a good deal if you old out for their free installation and $xx.xx off a set of 4... then it's mounted, balanced, nitrogen filled, free top offs for pressure, etc etc...
I've don't the sears thing ordering tires one at a time with promo coupons on each transaction that gave discount usable on next transaction, so on... got $560 in tires for under $300 on that one.
I'd say biggest issue is your roads and driving habits. If you plan on tire protection plans, drive through construction that leads to nails and such, hit curbs, etc, maybe and local independent is best since they take better care down the road....