Anyone who's thinking of getting a compact camera bag for their equipment should definitely give the F-3x a trial, once you try it, you will love it. Even though it states compact, you will be amazed at the amount of gear you can carry, I'm mostly impressed that I could fit a 1) Canon 10D w/28-70 f/2.8L attached 2) 80-200 f/2.8L 3) 100 f/2.0 4) 50 f/1.8 and 5) hoods for the L lenses all inside the main compartment. Then I had my 420EX on one of the outside pouches, and charger on the other, with card reader and other small gear in the front pocket!
I personally like the ballistic nylon, I believe the canvas ones are very nice as well. Everyone has got to give this bag a try!