Yes, it is housed in plastic casing. However, the plastic used is very sturdy and you won't be breaking this unless you're stomping on it like a maniac, in which case pretty much any pedal can break.
What comes to sound, this octave fuzz is a pretty faithful recreation of the legendary Boss Hyper Fuzz FZ-2. As such, it sounds absolutely monstrous, in the best possible way. There's a reason why these little units have become something of a cult hit.
There's two different selectable fuzz modes and a boost mode. Fuzz mode 1 is kind of a heavy fuzz face style sound and fuzz 2 more in the style of the Big Muff. It bears mentioning, that while lots of praise this pedal's utility in doom/stoner kinds of sounds, it actually works really well for other kinds of genres as well when you bring the gain down.
However, one the biggest selling points of this unit is this one neat trick that even the BOSS FZ-2 can't do: there are two additional "secret" modes that clever people of the interwebs have found. They can be accessed by carefully sliding the mode selector *between* the different modes. Mode "1.5" activates *both* fuzz modes at the same time for an absolutely massive and gnarly fuzz explosion, while mode "2.5" activates fuzz 2 + boost, for a kind of a Jack White type super sound perfect for epic riffage.
Given the price, quality and features of this pedal, it's basically a no-brainer for anyone looking to expand their sound into grittier territories.