I've had a couple of TT bags in the past. Both bought and used for largish DSLR kits, too bulky for the gear I've been carrying about in the past couple of years, but good solid bags with quality stitching, hardware, and design.
I looked at the Citywalker 20 and it was simply much larger than I had any use for. The big issue I needed another g**d** bag for is that the E-M1 fitted with HLD7 simply becomes too tall a rig for any of the 10-15 other bags (!!) I have currently. They're all sized around the Leica M, GXR, etc: work great with the E-M1 when I have just the 14 or 25mm lens on it, but fit the grip and the 11-22 or any of the Leica R lenses and the camera sits on my desk looking for a place to live.
The Retrospective 7 also fit the camera, but differed from the CW 10 in being a bit bulkier on material, not space, and put the tablet slot in the back rather than in the front. From experience, I know that having the tablet in the back is a bad idea: the bag cannot conform to your side or back, it becomes a flat thing.
It'll work, and not piss me off too much. When I get annoyed enough with it, I'll find something else. If it doesn't, I'll use it til it falls apart or I sell it with the camera. That's how it goes with bags... ;-)
G
