We've taken a relatively traditional route -- partly because I WOH and it's not practical to homeschool the kids. It's theoretically possible because dh works from home, but given our personalities, our kids' personalities and our work needs, it's not a good fit.
That being said, we, too, evaluate regularly to see what's the best fit for our kids. We also are in pretty close contact with the schools. Both kids did K at the Reggio Emilia inspired daycare that my kids attended instead of public school. But the reasons behind that were very different. Ds needed an extra year in a 'safe' environment with familiar children and familiar routines. He's got a late April b-day, isn't the most socially advanced kid, and just needed more time to mature socially. Dd needed a full day K to keep her very active mind and social side engaged. 2 1/2 hours of K would not have been enough for her.
Both are fine now in public school. We'll see what happens next year -- dd is the one I'm worried about since I'm not sure they'll be able to meet her needs going forward. But we have a plan going into the year and we'll see.
For you, your son is a very young 3 right now. Many 3 year olds don't need (or do well in) preschool. Many do. If you aren't feeling a strong need to put him in preschool, I wouldn't. This may change by the end of the year. 3 1/2 can be a notoriously difficult age, and some children really begin seeking out other children to play with. If you're part of groups or activities that give him the socialization he needs, or if he has a lower need for socialization, he may not need or want preschool next year either.
In terms of the schooling options, my best advice is to visit the schools and talk to the teachers. That's as important as research about different schooling forms. Talk to other parents who have children who attend there. Talk to other parents who have had children attend there (and moved on). Parents who are at a school often have a vested interest in believing everything is great when it's not. If all you know about the schools is what the serve for snacks, that's honestly not a very good reason to choose one vs. the other. Many parents in our neighborhood opt out of our public school based solely on its 'reputation'. No matter that this reputation is 20 years old and no longer valid. If they visit the school, talk to the teachers and parents and see what it's like and then say "no", I'll accept it. But it ticks me off when they write off our school without any real research.
Also, be very discerning about research -- it's almost impossible to compare research on public schools with research on homeschools because the two populations aren't comparable -- all the kids are included at the public schools. Only the parents who choose to participate are included in the public school research. It's well known in social science research that there's a distinct bias for people who choose to be part of a study -- they're not like the general population. That doesn't mean that homeschooling isn't good or can't be right for you, but do know that there can be issues with homeschooling, just like there can be with public schooling or private schooling. You need to go into each type of experience with your eyes open and looking at whether it's working for your child and for you.
Finally, as far as the 'wealthy' parent thing goes -- do you really expect that to be better in Montessori? My experience (and it is only my experience) that issues of money and 'keeping up with the neighbors' increase, not decrease, with private schooling. It's not true for all private schools, but children who go to private schools are often wealthier. Depending on how much the school costs (private schools around here run from ~$4,000 a year for religious schools to $24,000 a year for the really high end ones), it will be more or less of an issue. How many poor kids go to these schools? How many go to the public school?