Albums are GREAT to have - yes we can pull a LOT from the internet (especially with the free sites available now). My concern is that these are creating a fair amount of confusion.
For the greatest *consistency* in style, presentation, use of the material, the ideal is to pick one set that you can follow all the way through, whether AMS, AMI, R&D, etc. Obviously some are going to be better for a
particular situation than others.
Then use the internet for follow-ups, stretching an interest, or a modification idea for your particular situation, knowing that you have a consistent foundation.
In the different album/training
options, there are differences from one album to another (even the same
subject for the same age) and in how different "groups" present a material
(ie many albums present 5 pair of land/water forms at primary; AMI presents
3 pair, with the remaining ones left for follow-up by those who are
interested as a discovery).
There are also re-interpretations for specific
situations posted on individual blogs, which are great for that situation,
but perhaps not for others - and then those without Montessori training are left confused and re-interpreting
things all over again, thinking that we're making sense of things, when we've really missed the entire point (I've been there!). I remember totally messing up the elementary grammar
material and not understanding why the children weren't latching onto it. As
soon as I re-did it the "original way" using one of Montessori's books as a guide,
the children were a lot more interested (at least those whose interest I
NOT ONE GUIDE:
There is not one album or manual for every subject even
for one age group - so there is no "Primary Montessori Album" that covers
everything. Each album should specifically address age (primary, elementary,
(I'm less familiar with infant/toddler, just enough to not want to speak for the
albums at this age at this time)), and be for a specific subject. So Primary Mathematics;
AMI elementary albums cover 6-12. Other groups separate
the elementary continuum into 6-9 and 9-12 - an unnecessary and artificial separation since the differences from lower to upper elementary are not that
distinct, with many overlaps and it is added expense for the purchaser. Also the same album material really covers all years when the keys are used as the primary focus, with extensions for particular ages and interests.
All primary can be used
for 2 1/2-6, even when they say 3-6. Most primary children transition to elementary anywhere from 5 3/4 to just before their 7th birthday. If you have a continuous set of albums from the same source, you'll have a smoother transition.