Pros
1. you will learn a lot if you are put into a good team. 2. usually work culture is pretty good in the R&D team. 3. colleagues are mostly helpful. 4. don't have to keep slogging.
Cons
1. company pays you just enough so that you usually will not do all the tiring work of finding a new job. 2. when you are in development in a considerably big team you will usually not get important feature to develop on your application. It's quite hard to be like in the forefront of a feature development if you are a junior. 3. you have to be very lucky to be in a team where not too many senior tech leads/architects are there so that you actually get exposure to develop and design a feature from the forefront and someone is just mentoring you. 4. the problem in the R&D teams are technical architects, they don't move and go to a new team so that the juniors can get the chance of showing their capabilities. As i said one has to be very lucky to get better opportunities in the team