Having used both, I personally prefer the Chrome for very heavy loads (the chrome has a much wider, padded strap with a wide connection at the shoulderblade), and consider it fairly comparable to the timbuk2 otherwise. If it came down to buying one of the two, it would simply depend on whether or not I planned on using the bag for 8 hours a day as a messenger, or an hour or two as a commuter. There is no doubt in my mind that i'd rather wear the padded chrome for 8 hours, but the timbuk2 is a very comfortable bag for casual use.

That said, I would not use a messenger bag for very heavy loads either way. I'd use something that the bike carried the weight of.