This is an interesting subject; I'll try for a more focussed post this time . . .
But, all things considered, are there more advantages than disadvantages?
There are aspects that would feel like advantages. The satisfaction of belonging to an elite group, the security of clear rules and regulations (at any one time), the comfort of routine and community. Misery's posts in particular give a warm picture of the jw community.
The big disadvantage I see would be the doubts. I cannot imagine that any jw with a reasonable education wouldn't have them. Answers like "wait upon Jehovah" and "more meetings and service" couldn't wipe them out. It would be like seeing things out of the corner of your eye but being forbidden to turn your head and look.
Young people most of all would be hampered by never being allowed to test their own judgement and initiative. And if for any reason you finally could no longer live by someone elses' rules, well, those are covered every day in the forum. The choice between living a lie and losing family, friends and community to live in a world you have been taught to fear.
I am in awe of the courage of those who take this step.