Vantaggi
Hirey is a start-up company and with that is a real ability to affect things. If you are a person who likes to fade into the background this is not the job for you. In contrast, if your goal is to affect change, chase opportunity and grow with a company that is "the future of hiring", then this is the place for you. Culture here is not set. Coming to this company early mean you are a huge part of the culture and to change it you will need to be open and honest and ready to throw your hat into the ring.
Svantaggi
If you aren't able to handle growing pains and open dialogue then it will be hard for you. Like I said previously don't expect to fade into the background. If you aren't proactive this can certainly be a scary place, but if you are here to add something to the company and have what you do matter then reach out.