My experience was great. I got paid to do 6 years of learning and experimental work by the government (thank you DOD and NSF) on the coldest states of matter in the universe. I traveled the world for free and hang out with Nobel prize winners. I was surrounded by bright and a few world-class brilliant people. I didn't have any real deadlines. I got to write and publish papers trying to explain my work.
Now, the post-doc/professor rat race is only for those who are truly called to the field. My plan was PhD->industry the whole time.