Vonnegut. Who's read him, and why? Does he hold up or am I gonna be pissed off if I read him?

To be honest, I am getting fed up reading "classics" and "the greatest writers of all time" that piss me off or are disappointing. Dean loves Vonnegut and while appreciate him as a character, he is also pretty messed up, so... I don't know if I trust his judgement or that of the SPN writers. Please discuss. Thank you