I don't have any personal experience but I've read bad things about BuyDigs "bait and switch" techniques. There were a lot of frustrated people last time they offered Panasonic G5 on sale.
I haven't bought anything from buydig (no S) in the past couple years, but previously I bought ~$1,500 worth of stuff from them between 2000 and 2007 and never had a single problem. They were based in NJ so no sales tax for NY residents, and I even got something the very day after I ordered it. Maybe they've changed, but I never had any issues with them.