Best of both worlds; the usual growing pains
Pros
People. Inclusion isn't hyped up -- it's apparent. Flat structure lends itself to a jerk-free space. Not a ton of turnover, lots of interviewing -- OGs and newbies get along because everybody's socially well-adjusted and here to work. Culture. Founders are pretty transparent and have families of their own, so they are good about work/life balance. Food/snacks, standing desks, health/vision/dental, gym reimbursement, professional development perks like all the big companies. Small enough that we can eat together, but not cultish about it. (No "scarlet letters" for disagreeing...heck, arguing might earn you points around here). Real Work. No vanity projects here. You will get to dig in and try different things; learning quickly is a must. If you don't produce, it's immediately obvious. Pretty stable. Not really scared of the company disappearing overnight and each team is pretty solid in terms of skill and commitment to the company. After being burned out (or churned out ) of the big companies, Streak is a pretty good place to land.
Cons
Growing pains. It's still a start-up, even if an older one. Some things are in transition and you may have to step up to fill in gaps. If you don't have an ownership mindset or trust the Founders, you may find it hard to stay motivated. In some ways, you will be your own boss, so if you're not self-directed, probably not a fit. Picky when it comes to hiring, but that could be a Pro, depending on how you look at it. If you get you an offer, they really want you and think highly of your skills... But relative to big companies, this is not the highest paying job you could get in the Bay Area. If you're solely motivated by cash, try elsewhere or negotiate. They are "competitive-ish"