Somewhat related, I recently "switched" (or added) to a new-to-me camera bag brand as well. For years I have used Lowepro shoulder bags. I owned two or three other brands (Tamrac, Tenba, etc.), but my main bags have always been Lowepro.
However, ever since I purchased my little T3i with a couple of kit lenses I am now on my third Canon brand shoulder bag. Ironically I couldn't find a Lowepro shoulder bag in the right size for my latest setup, so I ended up experimenting with Canon bags.
While I had a somewhat similar issue regarding finding the right size bag when I experimented with m4/3, I was able to use one of my Lowepro bags (Adventura 170 I think). This time around I have had a tougher time finding a right sized shoulder bag. Also, I noticed these Canon bags seem to be well constructed for the price. I never considered purchasing a Canon bag in the past because I never owned a Canon camera prior to this T3i.