Pros
One of the reasons I chose PatientPing was because I came from a really mission-driven culture and I wanted more of that at my next company. I'm happy to report I was right about PP in that regard.
There are nerf guns but they're used at a rate that it isn't annoying. Fun place to work, but still work focused. No bro culture here, which as someone who is new to startups this early stage I was relieved to see.
Executive leadership really seems to listen to employees. When I started the CEO asked me about how I viewed the culture here because he genuinely wanted to know what we appeared to be to someone on the outside. I appreciated the gesture - he brought it up (anonymously) in a company wide meeting.
One item I had mentioned was how quiet the floor was - this is something I've seen echoed. It's not silent, but most days you would be hard pressed to have a call with anything remotely confidential on the floor. The upshot here is that you never need to grab a conference room to concentrate.
Cons
The downside to a quiet floor is that you DO need a conference room for calls. Right now its easy enough to get a room, but I think as the company grows it will get difficult to get conference room space.