Take a tour of both. The Montessori school in my town is so impressive. They teach the child to read when he shows certain readiness traits, which means the child typically starts learning to read at age 3 1/2 to age 4. No daycare center does that. The child gets instruction usually once every 4 days for a good 30 minutes. the school I observed had a full time reading teacher and she kept track of each child and what they had learned and were learning. It was well thought out and there was a particular procedure followed. Very effective.
They also teach some math.
The kids learn to whisper and play independently. They do interact with each other, it's just quiet in the classroom.
They teach the children in small groups of about 5, although reading is usually 1 on 1. It can go to 5 kids, I also saw an exercise another day with several kids who were all at the same level.
There were 30 kids and 3 teachers.
The children work with puzzles and other toys. Just go observe--I think you will choose Montessori if you compare the 2 possibilities--dayscare or Montessori. I was quite impressed!
About that language development and creativity other respndents mentioned--I think Montessori expects that the parents speak to their kids and that's where the language development occurs, at home. Ditto with creativity. Tell me how there is going to be much creativity going on in a daycare center. Nor did I observe the Montessori classroom to be "academic". Sure they had puzzles and stuff on the shelf and the kids picked up their activities on trays, which sets the boundaries for personal space and kids learn not to violate that. But this nonsense about letting 2 year olds just "play", well that is what they did at Montessori school I observed. They were outside a good hour interacting with the other kids and having fun running and exploring, etc.
Just because a kid is taught for maybe 40 minutes a day, that is hardly a bad thing. It makes me laugh when I hear this "let the kids have fun" line. What, learning is not fun? Since when? Kids enjoy a challenge and they like to learn. It doesn't happen often enough for the child to consider it boring. You have to wonder what is wrong with poeple--what, don't they like to learn? Where did the myth that it is "pushing" a kid to teach them to read young? Just do it like it's a game and they are raring to go! I did this, and my kids enjoyed the whole process. It is all in how you approach it.