Ehhh, you know what? I've done both (and I actually did work on my own projects in my own time while doing A).

B is actually better.

There is an indescribable psychic toll that working at a megacorp takes on you. Daily I would wish for the sweet release of death rather than deal with another god damned conference call.

Now I just get a little cranky when I've been working for too long or someone's being an asshole.

I suppose I could try doing my own startup, but that's terrifying.