I bought my Emonda off the floor from a Trek dealer that I have a huge amount of respect for. I go to them for almost everything.
I bought my Giant Revolt off of Giant's website and had it delivered to an LBS. When I picked it up, the front derailleur cable had like 7 inches excess that they wound around the frame so it wouldn't stick out and the rear mech wasnt even close to being indexed. I didn't even bother having them fix it properly because I didn't trust them to do it right seeing how they delivered the bike to me.
My next bike was from an online only brand (Fezzari) and it was assembled perfectly and even had the mechanics info handwritten on a note in case I needed to get a hold of him.
I'm handy with tools and do pretty much all my maintenance and repairs myself but if I wasn't, I would be super leery about buying any bike from the internet, big brand or not, without seeing it on the showroom floor and giving it a test ride.