Perhaps the first thing to establish are the rules for acceptable carry-on baggage sizes for the airlines, destinations, and booking classes that you use most often. Additional information that is good to have includes how picky they are about enforcing their rules. That is crucial when every item and bag that you are bringing is on the limits of both volume and weight restrictions, especially when each of your bags is likely to be carrying something that you absolutely do not want to entrust to anybody else.

Every different type of bag comes with its own set of compromises. I also have a B&R 2-wheeled carryon that holds my Tom Bihn Cadet laptop bag (carrying my laptop and other electronic paraphanalia) threaded over the handle and fits wheels-in on 737s, 320s, and larger aircraft and sideways in Embraer 190s that are typical *A fare here in Europe. Volume-wise it keeps me within the official rules, but adding a full-frame DSLR with normal and telephoto zooms to the rest of what I need for sustainable travel puts me over the weight limit if I include enough clothing to be sustainable for a week or more (summertime). My wife has a very light Samsonite spinner that is just a tad smaller, but only about half the weight of the B&R. I am not aware of a better combination of weight and external volume for a spinner bag. If we need more internal volume and less weight, we go with the Tom Bihn Aeronaut 45, but that means that everything needs to be carried instead of rolled.

If I could count on being able to bring 2 full-sized carry-on bags with one being a spinner and the other being able to be carried in a stable manner on the spinner bag I would probably go with a B&R spinner for clothing and personal items with the Peak Design Travel backpack for all of the camera and tech stuff. The B&R spinner will be more relaxing to move on smooth, level surfaces than what you have now, and the Peak Design pack should thread nicely over the handle and be held in a more stable manner than your current setup.