I'm OK with buying fairly inexpensive machines online, but anything that's going to cost more than $600 or so, I want to buy from a local dealer.
I purchased two Brother machines from Amazon (a CS6000i and a PE-770) and both worked fine right out of the box. For my Janomes (6600 and 3160) I bought them through the local dealer. They've all been good machines and I don't regret buying any of them. (The CS6000i now belongs to my niece and nephew but the rest are all still mine and used regularly.)