The longevity of it probably depends on your sense of humour. If you find those utterly idiotic Garry's Mod videos, full of flailing limbs and exaggerated facial expressions and non-sequiturs, to be the height of comedy, then you'll probably enjoy Goat Simulator a lot more than I did, or at least...
+Stupid; stupid fun
-Gets old real quick; -Pretty pricey for what it is