Looks like they've modelled it on the rolling Lowepro version.
Be aware that the more expensive models often have better padding in the harnesses, thus reducing the "drag" on your shoulders. Plus they are made to sustain continuous use and are built like tanks, meaning they'll last for ages.
I have a Lowepro Minitrekker, that I've had for well over 20years and it's still going strong. Paid about $300 at the time - and I thought it was overpriced then! But it works out to $15/yr - bet you'd be hard-pressed to find even a cheap copy at that price, every year for 20 years!
It fits my Bronics GS1 kit perfectly - 3 lenses from 65-250, 2 backs and a Polaroid back also.
I can also use the following 35mm kit consisting of my EOS1 w/grip, EOS5D w/grip, 300mm f4, 28mm f2.5, 17mm f3.5, 24-70mm f2.8, 180mm f2.5, 90mm TS-E f2.8, Macbook Pro 13", umpteen rolls of film, d***** cards, my Kodak Junior 620 folder and film.
Only thing it won't take is my Manfrotto 055B tripod - have to carry that in it's own bag.
Sure it weighs an absolute ton, but it all fits.