I'm doing great with my current startups now but several years ago I founded a very promising startup which almost immediately got many acquisition offers in the high six figures and low seven figures. I, of course, took all of this to mean that we were onto something and were sure to get very wealthy in short order.
That didn't happen. What our app did got simply duplicated as a feature by an industry leader in software for our target vertical and that startup rapidly went from extremely profitable to bust.
TL;DR: Unless you're financially secure take the money.