This is my first experience with Discount Tire (in Fremont, CA), and I was very happy with the service. I like the fact that you can set an appointment with them on the internet.
I had ordered 4 Falken Sincera SN-828 from discounttire.com, they took my car in, indicated it would be ready in 45 minutes. I returned in 45 minutes, and they didn't have my car ready - they said that they didn't have the Falken's in stock (though their computer indicated that they did). To make up for my inconvenience, they upgraded me to Kumho Solus KR21 - which costs almost 40% more, at the same price as Falken's.
The Kumho's feel like a very good tire (only 100 mi on this) - good noise and grip on dry/wet pavement. Haven't tried em in snow yet.
I have always used Costco in the past - but I have found their service very deficient when it comes to honoring road hazard (I have had Bridgestone Potenza's - 60K life tires - fail on me in 15 K miles, but those wore out so fast, and they only paid for 1/5th of the cost of new tire, as refund is based on the usable tread left on old tire - this is ridiculous). My car has no alignment problems, obviously the Potenza's sucked, but I find it crazy that Costco's basis for the refund is wear rather than mileage. I also don't like the fact that you have to leave your car for hours with them.
I am a America/Discount tire customer for life now.