The main thing to remember is that typically early stage options for an engineer will make you a bundle iff everyone else gets paid (often first).

When things go badly, or even just not well, it doesn't matter what your plan was or how transparent everything is - the founders/board may be staring down a choice between folding the company up or decimating the equity of everyone currently holding it. It's a pretty easy decision usually. The good ones will take it on the nose with everyone else, the others ... well they aren't taking the same hit.