Wow 2500 for a year is a great price. We were quoted a maximum of 12000 so I'm guessing every institution sets their own. It is 1500 each year for preschool (under 3) for one day per week.
We decided not to proceed because we were concerned about the transition to a non Monti primary school or high school (as would eventually be needed). And to be honest at one of the open nights we went to where they had ex students speaking about their achievements, none of them really impressed us. Shocking thing to say but truthful. I understand that schooling can only go so far and a lot depends on the individual child and parents, however I thought they could have rolled put some high achievers for that night.
Also my hubs took a lot of convincing that a school situation where the children decide what they want to work on is suitable. I personally had no problem with it but he's a highly structured person and it made his head explode.
It is just so great to hear that other schools are incorporating more progressive methods of learning. I've not had any exposure to them since I was at school so really great to hear there may have been some changes. Whilst I don't think Montessori is for us specifically I think some of the core principals are great and warrant incorporation either in a classroom or home setting.
Best of luck with your decision the only thing you can do is ask everyone their opinion (as you have) because they differ so drastically. Do a lot of research - there's a book called montessori Method you will want to have a read of and go to the open days to see it on action for yourself.