HSLD, I used to work in a shop. What it comes down to at that price point is what fits you best. Pretty much every bike in that price range is going to have the same frame material, and the same componentry. They'll likely be made in the same thai factory (likely by Giant).

I'd consider how the frame fits, as they often use different geometries. You can tweak the seat postition, stem length, etc to a point but it's moot if you don't start with a properly fitting frame.

Another important consideration is the shop. Most offer some kind of service warranty, that's a nice thing that could save you a few bucks per year on adjustments. If you're riding a bunch, you'll need the bike serviced every once in a while. Another important consideration with the shop is how much time they spend with you on the purchase. Are they willing to swap parts? Did they take time to fit you on the bike? etc.

Having said all that, Giant makes some of the best bikes I have seen in that price range.