Pros
Strong leadership, open communications, encourages entrepreneurial thinking within the team, opportunity to be part of the growth & direction of the company, works to hire highly qualified people.
Kontras
Has the usual startup challenges - resource constraints, controlled growth issues, people sometimes wear multiple hats (not always a negative), waves of high hours, marketing. IMHO - If someone enters a tech startup without these expectations, to one degree or another, then they should probably not work for a startup.