My brother has a friend that's a carpet installer. I asked him once about Empire, he said that they charge double what other companies charge, then have a "sale" for half off, or "buy one room, get one free". So if you buy during a sale, you'll pay about the regular price you'd get from another company (which is still more than a sale price at another company), if you don't buy during a sale at Empire, you're really ripped off. Either way, you're almost certain to get a better price elsewhere.
The only way I'd use them is if I needed to replace my carpet in a hurry, and I can't think of a reason that I'd need to do that.