Pros
After more than 10 years working in finance it feels like getting out to the fresh air. Small team, no politics, no "business", technology first. Team is good, the effort people put into the work is very transparent. People don't try to be better than everyone by putting everyone down. It is not a zero sum game as it usually is where IT is a cost centre, if company does good everyone wins. And it's open source! Everything you do will stay with you as long as you want.
Cons
Again, it's a startup. There is very short notice to be fired so if you are not confident you can deliver better not to trade your current place for QuestDB. There are also some geeky element to what is done here, if you are tired of the technology it is also not a good place to be.