Bandizip can open and extract RAR5 archive formats for free.
B1 Free Archiver has added RAR5 support to their Android version and soon will add it to their Windows version.
HaoZip (Chinese version) fully supports RAR5 archive formats, hopefully will be added to the English version.
7-Zip hasn't been updated since (2010-11-18), the project is pretty much dead now.
Most of the development is now done by PeaZip project which uses 7-Zip open-source code.
I personally like HaoZip better because it supports many features not offered in others for free.
Enjoy!!