Pros
The only pro is that if you've been shouted at or belittled by the CEO in front of an entire of people or left so mentally exhausted from being forced to work so much unpaid overtime from such a demanding workload, that there is someone else there going through the same thing to provide a shoulder to on. God knows you will need it.
Cons
Endless. The CEO is nothing more than a bully and loves the power. You have a report due? Doesn't matter. She will get you to go to the shop to buy her lunch. She even sometimes brought in her screaming toddler who would run around in the office opening doors whilst people were having meetings. She expected the other seniors to babysit her devil spawn whilst she had client calls. Don't you dare ever speak a slight negative word though. Not about anything. Ever. A toxic positive culture was promoted. If you said a slightly negative thing about anything, you were dragged into the office, labelled as a trouble maker and and got your wrist severely slapped. The CEO threatened to sack anyone who discussed salary (ILLEGAL). Job adverts boast about 20 days holiday (it's the legal min, Sam. Just an FYI) and annual pay reviews. You'll get a pay review, but it won't change. Senior staff are forced to work OT with no pay. They are bullied into doing so. A 'bonus' is promised at interview - this is £100 every 6 months. Pathetic considering the literal sometimes hundreds of thousands some of the scientists each bring in and the free hours they give the company. Lab staff are often hired straight out of university. They often got applications from older people but younger people are hired as an excuse to pay them less and because they're inexperienced with HR. As for the scientific validity of work that other people have mentioned, I can back that up. The CEO will make staff repeat data and then cherry pick data that looks the nicest to present to clients so they return to the company for more projects. I could go on. Honestly, after I left, it took over a year to regain any form of confidence as a result of working with this devil woman. If you value your mental health in any way, avoid this place at all costs.