Have heard good reports to toughness of Joyetech Cuboid 150w.
As an owner of the cuboid, it is my main device. It's not perfect, but it's good..
The good: rock solid mod. It's always performed, and not stopped. It's made of stainless steel. They place the electronics between the batteries, so it's just a tiny bit wider than two 18650's side by side. It has rounded edges. It can be upgraded to 200w. Spring loaded 510 and easy access battery door make switching batteries easy.
The bad: I got the black version, and the paint is really thin on it. It has no "feet" on the bottom, so the bottom of the mod shows the stainless. Since it is made of stainless steel, it is heavy. The menu system is not the easiest to learn with menu options down three layers (I.E. three clicks for menu, right button to switch to temp mode, then right button to switch to stainless, then left button to switch to ohms then left button to lock the ohm for temp... confusing, but you do get the hang of it.. The screen is not recessed, in fact, it protrudes from the case and can scratch. So, if knew now what I knew then, I would take a glossy cellphone screen protector and cover it before using (after cutting it to the correct size of course).
So, if I had to do it all over again, I would get the stainless version, protect the screen, and find some sort of protection for the bottom....but I still highly recommend it.