I would like to know pros and cons of Stacks Project compared with EGA and SGA and whether it serves as a nice alternative to them. Since I haven't read both of these texts, my attempt to compare the series in the following is based solely on the opinions previously posted by the users on MO.
The following are the pros and some personal opinions about Stacks Project:
- It was written by many notable algebraic geometers of 21st century, and its content is up to date, with more pages on stack.
- At this moment, the text contains more than 4500 pages, and its completeness ties with EGA and some (probably not all) volumes of SGA combined. (supported by comments of Prof. Vakil and Prof. Emerton in MO post The importance of EGA and SGA for “students of today”)
- It is written in English, so it is a bit easier to read for non-native French speaker and therefore less time-consuming. The fact that it is less time-consuming is important, considering the fact that both series are quite long. (I admit that one should be able to read math papers written in French. Yet, when there's a nice English alternative, it's more efficient to read English one if you're more fluent in English)
- According to Stack Project Blog, the generality of Stacks Project is the same as EGA/SGA, (so it's more general than Hartshorne's text).
But there should also be cons, especially content-wise. Some volumes of SGA is probably not covered well by Stacks Project because SGA has about 6000 pages. I understand that some topics covered by EGA/SGA are not covered by Stacks Project because they are no longer considered important. But I suppose SGA 3 is still the inescapable reference on group scheme, and SGA 4 and 4 1/2 have the same role on Etale Cohomology, though I'm not sure about Stacks Project's coverage of these topics. Also, it seems Stacks Project doesn't treat Etale fundamental groups (SGA 1) and Monodromy (SGA 7) according to its table of content. If I'm wrong, please tell me so. In order to know the cons of Stacks Project compared with EGA/SGA, I would like you to comment on the following points:
whether Stacks Project really covers EGA well
which volumes of SGA it covers well and which ones it does not
whether there is any comprehensive, rigorous alternative to the volumes of EGA/SGA not covered well by Stacks Project (e.g. if Stacks Project doesn't cover Etale Cohomology as much as SGA does, does Etale Cohomology Theory by Lei Fu serve as a nice alternative?)