I have 2 of these, a 3 rung and a 4 rung version. I have them because it is one of the items my Son sells on his websites.
They are ok as a backup, they make good work benches and they are good as a 'deck' when doing ceiling work. At full tilt they can be a bit 'hairy' as you are relying on 3 hinges , so 6 points of failure. They can make some quite weird angles to get you out of the carp if required.
My weapon of choice however is the Little Giant 4 rung ladder. It is as solid as a solid thing impersonating a rock. Same item as they use when repairing traffic lights, but a bit smaller. I work out of an estate car, it lives on its side in the back of the car and takes up next to no space at all. It extends to a 14 foot ladder in multiples of 1 foot [combi ladder cannot do this]. Works on staircases and splits into 2 trestles , add a plank and you've got a deck. Yes , I know I have gone on a bit, biu Little Giant is the way 'upwards'......... :coat