Pros
Some of the positives are being exposed to many different technologies. You will learn new things all the time. Although it can feel like drinking from a fire hose. Rotating oncall is only 2-3 times a year for a week at a time. Days fly by because there are always calls coming in. Bonuses for passing certifications and reimbursement for the exam fee if you pass. Bonuses for positive feedback from customers. PTO or pay accrued for after hour work. Unlike other MSPs, billable hours are not a metric. Ticket counts are tracked but there are no quotas. Stocked kitchen with free food.
Cons
Lots of after hours work. No training. You have to learn by breaking a customers environment or finding out who has experience with your issue. Customers can be very demanding. Lots of time is spent supporting XP and server 2003 environments.