Im glad you asked this as I was thinking of asking this same question. My posts have often stressed the negative side of my experiemce as a JW. adn to be fair...there were good things.
I don't regret that taking care of the gift of life and ones body was stressed so much. As a result I'm not some jaded burn-out...rather, people always assume I'm much younger than I am and are always suprised when they find out my age. They say I've got good genes but I know it's also that I lived a clean life and haven't been kicked around by the world as much as I may have been.
I don't regret that I was able to know some very decent trusting people. They were willing to put their money where their mouth is when it came to living up to the principals they believed in as they were led to understand them.
I don't regret that I'm not afraid to speak in front of a crowd or walk up to a stranger and start a conversation.
I don't regret that in regard to material things " keeping one's eye simple" was stressed. I own everything I have and have no debts because I followed this advice.