I'm CTO at a startup and I've made a 180 on this in the last year. I used to paint a rosey picture. Now I feel it's my duty to give employees full disclosure on what they can expect: cash burn, runway, technical debt, what we likely can and can not spend time on, that potential stock options should not influence the decision making, because the future is impossible to predict and it's very likely to be worth nothing.

I do also tell candidates that it's an investment in themselves and a great learning experience. You'll get more responsibilities than in typical companies and you'll be very out of your comfort zone. If you're the kind of person that thrives in such an environment, and learns best by experience rather than by theory, then this might be for you.