Vantaggi
Diageo has the strongest portfolio of brands in the beverage alcohol industry which helps them generate lots of cash for new initiatives and product support. That makes it a relatively stable place to work. Most years they pay a good annual bonus to the employees, and the salaries are among the highest in the industry.
Svantaggi
Diageo is a really big company and like many big companies, they breed mediocrity in middle management. It's a very political organization and change is very slow. Most managers at Diageo say all the right things in dealing with their employees, but do all the wrong ones. Most managers don't respect work life balance, they don't actually coach and develop their people, and the annual planning and performance assessments are largely an exercise of requirement once or twice a year. The IT infrastructure is one of the worst in the fortune 500. Their PC operating system is windows 2000 (not a typo), the network doesn't have sufficient bandwidth, and there's absolutely no systems designed to enable work collaboration. It's been a mess since Diageo was formed, and it's only getting worse.