There are cons that are associated with the growing pains of being a start up and they're not negatives as such but to someone coming from a larger organization those might be challenging - for example, working at Glassdoor EMEA is a demanding job and it is not your typical 9-5. It also requires that you roll up your sleeves and pitch in where help is needed, even if it's not in your direct area of expertise (that means helping with external events, organizing team events to build culture and morale, etc). If you're not prepared to do that, this is not the place for you, at least at this stage of Glassdoor's growth.
Glassdoor reacts very slowly to feedback - it reacts, which is appreciated, but it often takes months (and in some cases years) of mentioning certain challenges in order for senior management in the US to take action. We are still small enough - let's not wait until things get too dire.
Then there are cons that in my opinion are preventing strong talent from staying and growing and they are the real challenges of Glassdoor EMEA - there are almost no opportunities for career progression (unless, in my opinion, you are an SDR and move into a sales / account management role) and it is a topic that does not get addressed well enough, especially for a company with the mission of Glassdoor. It is a topic that many people discuss amongst themselves and there is a general feeling of not being able to progress, but that management is vague about.