I've never used scheme before, I've only looked it up to see whether it's worth using as my scripting language for prototyping and systems administration. I've read about the scheme reports and various implementations.
I felt that the implementations are rather more important than the reports themselves, talking about r5rs and r6rs, however none of them seem too mature to get into? Example, all features are mainly documented as a Manual and not offered to user through proper documentation and/or tutorials (if you wish to call it that way). It keeps the newcomers away.
Recently I watched https://www.youtube.com/watch?v=3ndZcd3-9hw and I noticed that Andy Wingo, known for Guile, expressed his "unwillingness" to contribute back and implement r7rs. From my research, Guile is a pretty mature Scheme implementation however there is no straightforward introductory to the language itself or to Guile-specific features other than the reference manual.
The design of r7rs, from the perspective of a newbie, seems very modular and interesting. I wish that it becomes widely popular among Scheme users for a united ecosystem.
My words are unwise and only notes, sorry for any misunderstanding of misinformation.