I've always wondered about this. They look really bright from far away so I suspect that they're using something better than the standard 5mm LED strings. Has anyone seen them up close?
I don't know what they're using there, but I do know that there are indeed different products for the commercial markets when it comes to Christmas lights. Usually much thicker gauge wire, better water intrusion protection. Although, they seem to overdrive the LEDs as dimming becomes a problem with them over time, especially if they're used year-round