K.M.
Hello. My only experience is with full-time pre-school. My daughter just finisher her first year in pre-school. She goes full time and LOVES it. She loves her friends and the teachers. My first sight of the school made me reluctant to look at it for fear that it was too heavily into academics, then I checked it out on the inside. Yes, her school does have some academics - she can count in English and Spanish and sing in both languages as well, but she is also thoroughly exhausted in the evenings because she has played so hard.
I know my daughter is in out of necessity, but I have found that it is great for her - she loves to play with other kids and she has learned a lot.
I never thought I would send her to pre-school - just keep her in an in-home daycare, but it fits her personality so well. I guess that is the direction to look - what is your son's personality - is he independent? strong desire to play with others? need more activity than you can think to give?
One other great point - My weekends with my daughter are fantastic! I find I have so much more patience with her because we have not been together 24/7. She is more snuggly and we play. I have found a great balance.
Good luck.