I've used this for a few years now , and as a weekly gigging musician , pulling in PA and guitar amps it is pretty indispensable.
I previously used a "sack barrow" but the castors didn't perform so well on some rough car parks, and cobbles.
Criticisms . . . The brakes are not so great , they work on the front wheels which will sort of lock , but with a good weight on the trolley you still get some unpredictable movement.
Load - over time my pull handles have bent , probably when faced with small door sills , I keep meaning to whip them off and straighten in a vice , but it ain't so bad.
As a one man band , with carefully loading , I can roll into a venue and get the bulk of the boxes in , and then bring stands , bags and guitar gigbags in.
I use it to haul - either 2 sets of LD Maui 28 , or 2 Yamaha dsr 15,s
Plus one flightcased mixer , one flightcases pedal train junior , one guitar cab 1x12 and 2 stairville power led bars , which forms a fairly flat load with platform not fully extended , I can then put a tubemeister and cable bag on top , with minimal risk of toppling , albeit the load will be stacked to a height of 5 feet
It saves time and multiple trips - but is probably pricy for what it is- but mine has lasted 250 or so gigs , without any serious wear and tear , so if anything happened to it , I would buy another !
I can use it on stage as a platform for the mixer , by reducing base size, and then flipping onto one side , with the wheels facing to back of stage ,and placing mixer and lid on top as a sort of cantilevered arrangement .