Most frames will be made in similar factories. Unless you get a handmade (in Germany!) frame, which is somewhat common.

The components looks very solid on the Vilano ... the rear IGH and shimano hydro brakes are good.

What's the price difference. I personally wouldn't pay for the mark-up to have GIANT written on my bike.

Bulls (a German company) is online only and would most likely beat the GIANT at every price point.

http://int.bulls.de/en/

As far as welds being "crappy" as pointed out above, it won't matter. I buy my bikes to use and not to look at. I've only seen 6061 bikes crack under very heavy usage in the Alps, and I doubt you'll be doing that ... a frame cracking on a commute is unheard of.