Pros
I was stuck in big Mnc's with layers of hierarchy and it would have taken me years to get the kind of ownership I have here. I am involved in decision making and manage mid/ critical module.
Plus the growth is in terms of impact that you make, ownership that you take and not in number of years you spend with company
Cons
None that I could think of.
But, its a demanding environment - like most high growth startups have. So, ensure you are of the startup DNA. If you like a chill, relaxed life, better join a Mnc.