When I last rode 9 years ago, I commuted for a few months and did my own routine maintenance, adjusting the brakes and gears, lubricating the cables and chain, and truing the wheels. If I buy now I have 4 months before the commute begins to work on the bike, so I figure I can do it myself. The tires and inner tube on the Trek are new so no problem there.
I'm 5-8 1/2 and the Trek is 19.5 inches. The center-top measurement for the Giant is 18.5 inches. Based on an online calculator a 20" road frame is right for me, and 18" for an mtb frame.
Here are some pics of the Giant

