This was a far more difficult decision to make than I had anticipated.  After much research and review I selected the Athalon 21" for my new carry-on bag.  The bag arrived three days after I hit the purchase button and I must say I am very impressed with the quality of this bag.  The build is fantastic, feels so solid yet not heavy at all.  It's amazing how much stuff you can pack in the bag.  I packed an extra pair of shoes (shoe pockets on inside of lid), two pair of jeans, 5 t-shirts, 5 boxers, 5 pairs of socks, 1 pair of sweat pants, two dress shirts a windbreaker and toiletries with room to spare.  There are 4 elastic/mesh pockets on the interior bottom section.  There is another mesh pocket and the two shoe pockets I mentioned previously on the interior lid.  There is also a full length zippered pocket on the exterior top of the bag beneath the handle that I really appreciate for magazines or a book or what ever.  The two exterior side pockets are a bit larger than they seem in the pics on line and that is a good thing as well.  This is just a great bag from every point of view.  I am going to immediately order the 29" version as well, it's a no brainer at this point.

I compared this 21" Athalon to similar products by Ogio and Oakley.  The Athalon was priced lower and that makes it a terrific bargain for a high quality bag.