Circuit City always has the Motorola SB5100 free with activation, so what's the point of going to BestBuy and getting a Linksys when you can have a Motorola?
The Motorolas tend to be higher in reliability and generally they've always been the golden standard with the old CyberSurfer series etc. They have good diagnostic pages and tools in them to diagnose signal levels etc. and they're generally easier to maintain than other modems, and when something's wrong, it's easier to tell what the problem is. They're just easier than other modems and they're reliable, and Motorola has always been the top vendor in cable modems.