Three latches, one with ability to put lock on. Three extremely sturdy hinges. Strong metal edges and balls in corners. Thick walls and tight fitting padding for synth, and enough room for tools and PSU in separate compartment.
Oh, and did I tell you the case weighs a bit over double the synth that it's supposed to carry? One might find this a weakness, as AX-Edge is supposed to be portable, but the ability to withstand a thermonuclear warhead to the face is a must, especially if gigging around.
I don't think there is much more to the case. It will out last any soft gigbag, and only thing stronger would probably have to be built from solid titanium. The carry handle is nice, but I would have loved to have a shoulder strap or something to take the weight off my fingers, but other than that, just throw the synth in, lock the case, throw it to the back of the van, and you're good to go.
All and all, strong case to protect your precious instrument. I have nothing bad to say against it, as it fits my needs more than perfectly. It's not the lightest option, but you get great protection in the trade.