Startups can be huge hit or miss. And the culture flows downhill from the CEO with little checks and balances. I've had friends who've loved the startups they went to - a lot of responsibilities, fast growth, equity, etc. But Iwould say more than half did not like it. Very little structure, changing priorities non-stop, chaotic environments, tyrannical CEO/minions. And most startups do not succeed - sometimes people forget that.
I would say, do your research and don't go there unless it's compelling. You can get paid more and more reliable equity if you go to a past startup but still growing company that's $1B in revenue.
It also depends on your life situation. If you're 24 with no kids or mortgage, swing for the fences.