OK. I work at a very nice, well respected preschool that basically caters to people like you.
It is only a half day preschool, and kids can either come in the morning from 9-12 or in the afternoon from 1-3:30. They can either come M/W/F or T/TH, and a few come all 5 days....regardless, they are only there for at the most, 3 hours. These kids all have SAHMs who do not work...that's the only way they are able to be flexible enough to drop off/pick up their kids in such a short time period!!
I gre up with 3 sisters, but none of us EVER went to daycare or preschool....EVER. I alwas thought when I was a SAHM someday I would not put my kids in, either.......until i started working at one.
It is SO GOOD for the kids, and every one of them gets SO MUCH out of it....socially, emotionally, intellectually, physically, etc.
Now, since I know you have twins, I am going to talk a little about that....we have 3 sets of twins in our program....and I think they are some of the kids who benefit most. It is so neat to watch them come in, stuck to each other like glue, and then over the months see them gradually start to really be individuals, and have seperate friends, etc., but then still at the end of the day, or snack, or quiet time, they are right back at each others side, still best friends with an unspeakable bond.
HOWEVER (and sorry this is so long), I think 1 year old is too young. The youngest we take into our school is 2, and I even think alot of them are still too young. I work in the 3 and 4 year old classes, and I think that is probably the best age, and when they would get the most out of taking part in this kind of program. Plus, it works WONDERS at getting them ready for Kindergarten.