I have probably 20 or so bags in my collection, including LowePro, Domke and Tenba, among other lesser names. They range from large, closet-dwellers that store gear but never leave home to mid-size jobs that would be horribly uncomfortable to carry for any extended period to little holster styles that protect a camera with long lens.
My bag of choice to carry in actual use is the Domke F3X. Every time. I have two of them and cannot wear them out.
I bought the first one, a chocolate brown with beige trim, used at a camera show at least 15 years ago. It has only one pocket that is permanently attached onto one side. The interior is the same as the modern bags. The second was bought new a few years ago. It is a classy green with genuine leather trim, and must have been a special edition or something. There is a pocket permanently attached to each side.
I use the first as my carry bag on vacations, urban walks, weekend jaunts when I need just a body, three or four lenses, flash, film and not much more. The second, looking a bit fancier, is used for weddings, bar mitzvahs, etc., when I want on my shoulder at all times what I need for the job at hand.
Oh, I may have a larger bag with more gear in my car trunk, but for comfortable carrying and ease of use on a job, the F3X is a winner, hands down.
You asked about removable partitions. There is only one thin, velcro-attached partition in the middle, and I use it to connect the two round partitions that are built into the sides of the interior. Occasionally, if I have a large camera with drive and lens attached, like an F90s and MB10 with 35-135, I have to remove that piece for enough space to keep the rig all together. Otherwise, it stays in place to keep a body/drive separated from other items. If there is another configuration with this single partition, I don't know of it.
And, yes, there is a zipper, but it is cleverly placed on the underside of the top flap to hold small items. Not having to fumble with a zipper to get to your other gear is a big positive.
Remember, this is a soft-sided bag that conforms to your body when slung over a shoulder. Protection is very good, but not the equal of more rigid types. Protection from rain is also very good.
I use it less for storage and protection but rather for actual carrying and ease of use, not being too heavy and a perfect size for what I may need for an assignment or day of shooting, I cannot imagine a photographer NOT having one of these. A couple of photojournalists who used 35mm and had to have some gear on their shoulder at all times introduced me to the F3X. They still carry one for their digital work kits that are small enough to fit.
