Flexibility to fit work around your home life when needed with work from home etc. Nice office environment when you're in the office, everyone gets on. When I was going through the interview process they were talking to me about "refract people" and it's true - there's definitely a type of person they recruit into the business. Plenty of egos but they're not really egotistical.
Great technology and although not for everyone, it really makes a difference to those that embrace it and it's quite an up and coming field.
Great tools used internally like slack etc.
Everyone has a company credit card for those little expenses that crop up.
Cons
No office parking that's free for those that want to drive, but that's what it's like working in the city centre! The office is on the outskirts of the city centre so still a bit of a walk if you want to go shopping at lunch time.