Pros
I worked at Propeller for about 18 months, and loved every minute of it. The people are really down to earth and pragmatic, no egos or awkwardness. The company prides itself on hiring for diversity and as a result of this, you're met with this huge family of very unique quirky people who just seem to thrive because of the open culture. It's a really challenging industry, and the team are pushing the boundaries a lot, but it was always "us vs the problem". I think it's because everyone cares about the same thing - almost everyone talks to customers on a regular basis. Like, daily. They're mates. I can guarantee you'll be working with very smart people who learn and adapt fast, and you'll have fun (lots of events, amazing food). More than all of this, Propeller has a "cold fizzy water" tap in the kitchen - I miss that tap even more than I miss the team.
Cons
The Sales and Marketing teams are based in the US. So if you're in a role where you're going to need to work directly with those teams, make sure it fits well with your personal life (family, etc). As the organisation has grown, the chasm between the continents (and consequently Product<>GTM) seems to have been quite challenging. This improved a lot in the last 3 months of when I was there, after they consolidated the leadership team to C-Suites who could keep things tight.