I have the tech XL, tech LT, and pro pac backpack. Bought them all from techtoolsupply.com
I'm an IT guy.
The XL has my electrician tools
LT has my laptop(s), tablet(s), general test tools, IT tools, tons of USB drives & CD's etc
backpack has all the misc things that might be needed for any situation or might not be needed at all.
I have a few things overlapped in all 3 like stanley knives, pens, scissors, level, 4 in 1 in the bags that don't have real screwdrivers.
As an IT guy I need to go int o a lot of offices and places where looks are as important as anything else. They look better than the Husky stuff I used to carry, although Husky bags aren't bad bags at all.
so for a few useful observations although I haven't had the XL all that long.
the backpack is heavy, it makes a good secondary bag but if you put a ton of hand tools in it it WILL feel like a TON of hand tools.
they all do a great job of staying up with the hard bottoms which can sometimes be useful but sometimes if you want to lean it up or squeeze it into someplace tight the bottom of the bag will get in your way.
The XL is not as convenient as the smaller bags as an everyday bag. I use it for stuff that doesn't need to come out often, like if I need to make a new outlet or get into something with security bits or whatever.
They don't do as well for bigger tools. M12 drill/driver is fine, M12 portaband definitely not. Most of my work doesn't involve power tools much more than a drill/driver so I like to keep the rest of what I might need in hard cases anyway as they stack better that way in my truck.