I am very happy with this bag! It was a quick enough knit, with the cabling keeping it all fun. I finished it a few days ago, and completed a lining with a ton of pockets a few days later. Yesterday I sewed in the lining, placed all my crap into the pockets, and took it to dinner and the theater, where a random woman in the lobby complimented it!
The wool and the button I purchased for this specific purpose at Weaving Works in Seattle when we were there for DBF's cousin's wedding. One of the only times I have ever used the correct yarn for a project!
I back-stitched along the cables with a double-strand of the contrast yarn. Other than the double-strand, I didn't even modify the pattern much:
I made the button flap longer and wider.
I made the handles longer by only one repeat (10 cables each).
The pattern seems wrong in two places: Purling should always be done on the correct side (there is a note about this on Ravelry) and I made the decreases on the second short side match the increases on the first short side.
Felting was resistant: I worked the bag in hot and cold water in the sink, without much shrink. I spun it in the washer, then threw it in the dryer until it shrank around the plastic netting. It could still have used more felting.
The only thing I would change isn't a knit problem at all. I should have made the lining from a thicker material: As it is, the lining is so thin that all my gear just falls out of it. A stiffer, stronger lining would have kept everything separate, and perhaps help the bag stand up.