The Giant TCR was (is?) their top of the line road racing bike. This one has the top of the line Dura Ace groupset. The Mavic Ksyrium wheels, although not tubeless, has the closed rim bed which means you never have to worry about rim tape and associated problems. It's also 11 sp ready like all Mavic wheels with HG cassette hubs.
$500 is a very decent price for this bike.