Well, he has 173 feedbacks, and 100% positive, so he seems like a solid seller.

If you can pick one up for close to the starting bid, it would be a great deal IMO. Retail is around $1,800 on those bikes.
It is hard to tell from the photos, but one question worth asking is if the Gates system is the old format or the new "centertrac" system. Not a deal killer, IMO, but worth asking.

As far as assembly, I'd assume it would be like any packaged bike - saddle/seatpost, handlebars, pedals, front wheel, then a quick tune up and final adjustments. If you're not familiar with basic bicycle mechanics, then a shop might charge anywhere from $40 to 100 or so to get it set up for you.