J-2 or F2?

I'm trying to decide between the J-2 and the F-2. The size seems right for my needs. Can someone list the specific differences between the two, other than ballistic vs canvas? Is the J-2 water resistant like the canvas? Why is the J-2 more than a pound heavier than the F-2?

I tend to keep bags for a long time (my main bag is a 25+ year old Lowepro) so I definitely want to make the right purchase and appreciate the help.

Thanks.
Mike

[admin]

There are several differences, I will post some pictures tomorrow. On the J-2, the side pocket flaps are bigger and have a clip closure instead of just Velcro. There are padded pocket insert in the side pockets. Inside the main compartment there is a heavy material lining (picture tomorrow). The front flap is a little more fitted, picture of that tomorrow too.

Pictures would be great, thanks. It sounds like the J-series is what I'm after, I like the idea of a bit more protection, as well as the clips on the pockets.