Without going into any detail on individual bikes, the one thing I would warn you about with BikesDirect bikes in general is the sizing. Nearly every bike that you find in a bike shop will be sized "center-to-top", which means the bike is measured from the
center of the bottom bracket to the
top of the intersection of the seat and top tubes. Most (but
not all, so it's extra confusing) of the BikesDirect bikes are measured center-to-center, which means the bike is measured from the
center of the bottom bracket to the
center of the intersection of the seat and top tubes. Center-to-center measurements usually end up 1 or 2 cm less than center-to-top measurements, so a size 56 at a bike shop would correspond to a size 54 or so on BD. A mostly reliable way to tell if a bike is measured center-to-center or center-to-top is by what size is considered "Large". A center-to-top Large is usually 56cm, and a center-to-center Large will usually be (subtracting the 2 cm) 54cm.
The most important feature of a bike, in my opinion, is not the componentry or what material the frame is made of, but is how well the frame fits the rider. It seems like you've found this out for yourself already. Fitment is one of the big reasons bike shops exist. Even if you want to buy the bike online, go to a shop and ask to test ride a few different sizes. If you find one you love, support your local shop and if they're good they'll likely pay the difference (realistically, sub-1000 dollar BD bikes are maybe a 100-200 dollar discount, not the 50% they claim) back in accessory discounts and maybe a free tune-up or two. If you're still set on buying online, at least you'll have some idea what size you really need (don't forget to take into account the 2cm sizing difference!).
If you'd still rather not go to the shop and you have someone at home to measure you, Competitive Cyclist has a fantastic fit calculator here:
http://www.competitivecyclist.com/za/CCY?PAGE=FIT_CALCULATOR_INTRO Note the results give you both "c-t seat tube length" and "c-c seat tube length". As you might guess, c-t is short for center-to-top (bike shop bikes) and c-c is for center-to-center (most - not all - BikesDirect bikes). For commuting I'd go with the French Fit results, but you can read the descriptions and decide for yourself. To avoid overcomplication, we'll only pay attention to the relevant seat tube length (c-t or c-c, determines how much your legs stretch) and the top tube length (determines how much your torso-arms stretch). You can ignore all the other numbers the calculator spits out. First, just find the sizes that fall within your seat tube length range. For example, if your results gave a range of, say, 53.7-56.2cm, you would then be narrowed down to sizes 54, 55, and 56. If there is no size 55 (which there probably isn't), then you're down to only 54 and 56. Now between those two sizes, find the one that best matches your top tube length range. All of this size info should be available on the BD website in what's known as a "geometry chart". If they aren't provided for some reason, please call them and ask them to provide you with geometry information. It'll only take a minute, and the benefit of having a well-fitting bike is definitely worth the time.
If you need a primer on the bike terms above, read up here:
http://www.intownbicycles.com/how-to/bicycle-terms/