Being able to choose a research topic that you are interested in and you believe would make an impact. The stipend from the research assistantship is enough to cover the tuition, housing, health insurance and daily expenses.
Cons
The exact experience is highly dependent on the research advisor and your style of doing work. In some departments, you have to choose an advisor before your program starts.
-We can completely choose our own hours
-for the most part, manage your own project
-Learn a lot every day, and achieving results is fun
-Tuition waived during the research assistant appointment
Cons
-Depending on your PI, can possibly be too restrictive
-Can be stressful
-Some departments do not handle student needs very well
-Lab work can be tedious sometimes