Pros
Like any tech company, there are far more ideas than resources to execute those ideas. The advantage is that if you're resourceful and demonstrate you can get things done, it's easy to gain significant responsibility early on in your career. At Alarm.com, you really feel like you're treated like an adult. Senior management feels approachable even to junior employees, and you won't feel like anyone is looking over your shoulder. If you earn it by working hard and getting your job done, you'll have all the autonomy you could ask for.
Cons
Alarm.com makes great products because its culture is so product-centric. As a result, engineers, product managers, and other employees on the product teams may seem more "important." Beware that if you want to work outside of product, you're going to have to work harder to get attention.