Pros
I've never been in a startup but I imagine that working at one is just like working at Atmosera. The CEO often says that we're trying to do so many things at the same time and most companies can only succeed at doing one, but it sure is fun! I like getting up and going to work every day because I have no idea the problems I'll run into and eventually help to solve. The newness of every day is refreshing. I have been in jobs that are the same old thing again and again, and yes there are things that are repetitive it is a new experience all the time.
Cons
I'd have to say resources. I think that would be the same with any startup though because you can't spend lots of money on things that aren't proven yet. Even so, having more team members might allow us to grow faster.