Lowe's carries Trex and ChoiceDek, which changed their formula about a year or two ago to help fix the color fade issues. Depot and Lowe's in-stock selection kind of sucks but they can order basically anything you want as far as product lines, colors, railings/posts/accessories/etc. If you want to special order anything go to Lowe's, depending on how much you order we can definitely save you a few bucks. I haven't ordered ChoiceDek lately, but Trex will usually have any special order decking sent to the store in a week or less.
^^^ Or talk to this guy. He knows his stuff