[AnotherMarc]

In addition to the considerations others have mentioned, I would say from a strictly expected monetary value, a successful consultant will make more money than the first technical employee at a seed stage company. So, if you go that route, you should have other motivations than maximizing your expected return.

As a rule, I don't even think it matters what the valuation was because generally the seed stage companies that should rationally expect to make money would have started with a proven team with prior successful exits.

I'm definitely not advising you away from the offer. I've been a consultant, worked at both successful and failed startups, and preferred both types of startups to consulting. But I still think the expected return is higher in consulting or being a top performer at a large (tech) leader. Good luck whatever you decide.