Well this is disappointing. I purchased the bag recently, and indeed, the dimensions are different from what is advertised. In my case it was 55x37x24. Now I have to worry about those extra 4 cm every time I'm boarding WizzAir. It may be due to a cheaper manufacturing process that doesn't correctly fold the hard bottom/back, but it's something I would've expected out of one of the no-name bag offers here.
Next in order of importance, different offers for this bag have stated a weight of either 1.9 or 1.7kg. Well, the kitchen digital scale says 1850 g. While personally not butthurt about those 150 extra grams, I hope in the future CabinMax will be more careful to not allow misleading specifications in their offers - especially the dimensions.
Third, the trolley handle. I guess the zipper section was a quick fix from the last version, for which I am grateful. Yet it could still use some improvements.
* First, security: it provides direct non-lockable access to the main compartment through a ~12x6cm hole - for the paranoid among you, more than enough for the random guy across you in the train carriage to grab small valuable objects from within without awaking you.
* Second, water-proofing: once the handle is out, you can only zip up the opening half-way and water can pour inside quite easily. Although it's a good idea to use the backpack mode during wet weather (avoids making a mess of the underside as well), it's an issue that could be easily improved:
My personal recommendation for a quick fix for the next model is to just make the zipper twin-headed and lockable, similar to two out of the three other zippers. A small increase in production cost, no need for a new manufacturing process (like adding a proper piece of fabric around the handle would probably require), and solves the two issues to 80% - lockable (at least symbolically secure) and splash-proof by zipping up the opening almost shut when the handle is out.
All things considered, it's a good bag, but I really hope they fix the depth issue (kills the bag's main competitive advantage) and throw in a second zipper head on the trolley handle zipper.