How did your kids respond to the way the materials are taught / the structure / etc.?
To be honest, sometimes not well. Some aspects of it are set up that children have to not only understand but demonstrate mastery over a small part of something before they are shown the next step. It's too early to see how DS2 will respond to that but DS1 wasn't too pleased. So for example when presenting sandpaper numbers you were supposed to do three numbers at a time and wait for another day for the next, when they could name those three. Well DS kept askiing what the next one was. He was also disinclined to perform. He hated being 'tested' or put on the spot so he would pretend he didn't know something rather than attempt it. If I waited for him to demonstrate ,astery. I'd be waiting a long time.
So we went with a 'follow the child' philosophy. He was showing us what he needed, just not in the tradtitional way.
I know a lot of Montessorians would be offended, but that just didn't work for us. I wouldn't be following the child if I didn't accept that that isn't how his brain is wired!