I cannot decide which reference I should use to map my gut microbiome 16S data.
Greengenes seems to be the best choice, but last time it was updated in 2013 and metagenomics has moved far ahead since then. Won't I be missing a huge part of biodiversity, if I use it?

Also, this [article][1] keeps me worried. SILVA and Greengenes have a rather small overlap in taxonomy. It makes me want to make my own reference DB, but that'd be a serious standalone project.

What do you use to map gut 16S? Is there really nothing better than these two arguably accurate ref DBs?

  [1]: https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-017-3501-4
Non-profit -> SILVA

For-profit -> RDP


Greengenes is dead, don't bother with it. Overall I think SILVA might be more accurate/up-to-date than RDP. However, SILVA has a costly license for non-academic settings..