Pros
One of the things I loved the most about working at HackerX was that I felt like my work mattered - because the team was so small when I started (there were only like 7 of us back then), my work every day had a big impact on the company, and that was a good feeling. The environment is cozy, collaborative, and exciting, especially if you love to travel.
Cons
There isn't a whole lot of room to grow upwards unfortunately due to its small size - I went from being an unpaid intern to getting paid hourly after a few months, so that was a nice little promotion...but other than that, they don't need tons of people in management so there are not a lot of long-term career prospects. Additionally (depending on what you do), the work can be quite repetitive, but you'll find that in virtually any entry level job.