I've had a chance to take this bag out but haven't actually used it yet for painting/sketching (only because of the weather keeping us from taking the time to stop and sketch).
I have my sketching/painting gear packed in it, my wallet, and a camera hooked to the outside for quick access. The bag is going to work out wonderfully; however, I do find the strap hurts my shoulder. Due to nerve issues in my neck and shoulder, I can feel every little ribbing in the strap and it just feels like it's cutting into me. I'll have to come up with some sort of padding on the area that would naturally rest on my shoulder but other than that, the bag is wonderful!!! Not too big but definitely big enough to carry what I need with room to spare.