Pros
The greatest pro is the chance to work with incredibly smart people. When I got here I joked that the people here were smarter and better than me at things I didn't even know I was supposed to be good at. There's zero ambiguity as to how well any given employee is performing because of our very specific performance metrics. There's career flexibility and the company is will to experiment - if you have a role or function you think needs to exist you can propose it. There's lots of access to senior management if you have something to say - and the culture doesn't punish mistakes or questioning the status quo.
Cons
Get over the work/life balance thing. The successful people at HubSpot tend to be highly committed and their jobs are always somewhat on their minds. It's part of what makes us so innovative and creative. If you're looking for a job that you leave at the office at 5PM, this probably isn't for you.