3 yr old prechool-- how to decide?

So...my latest "obsession" has been trying to decided if we should enroll Zachary in 3 yr old preschool or not. Here's my thoughts: He is absolutely ready, BUT, is it really worth it? In doing some research on the local preschools, I have basically come to the conclusion that if you send your 3 yr old to preschool it is NOT to learn academics, but rather to learn socialization. Only one preschool, of the 4 I checked into actually has an organized learning time with a "curriculum" they actually follow (for age 3), meaning he would be learning and practicing colors, shapes AND letter recognition and phonics.

I am very sure that Zach does not need help in the socialization department, which some 3 yr olds really do need. He already does well in church Sunday school class, play group, MOPS and play dates, plus he did VBS for the first time this summer and loved it. So I'm thinking, why on earth should we spend $130-235/month for him to play with someone else's kids somewhere else 2 half days a week??

On the other hand, baby #3 is right around the corner, and some of my Mom friends are gently encouraging me to enroll him, so that I will have a "break in the madness" for 2 half days a week. If you ask my Mom, and I'm sure she'll tell you with a smirk, I am a terrible decision maker. I guess this follows suit that I just can't seem to make up my mind...I must have changed it 3 or 4 times already. At the moment I am thinking that we'll wait until he's 4. I am also thinking that having him at home with me, Sydnie and baby might "increase the madness", but it might also be helpful to me, too. i.e. built in play mate for Sydnie, diaper and burp cloth getter for Mama.

My Mom once told me something my Grandma said to her when she was struggling, with no luck, to potty train me. My Grandma said this "I've never met a child that wasn't potty trained by the time she started high school!" Along the same lines, I hear Grandma's echo from heaven of "With or with out 3 yr old preschool, Zachary will make it to high school !" Some times wisdom comes to us in the most unusual forms. Thanks Grandma :o)