If you feel the need , but I would not use that , I would use this ftp://ftp.dd-wrt.com/betas/2017/06-01-2017-r32170/asus-rt-ac68u/ its betas/2017/06-01-2017-r32170/asus-rt-ac68u/
Why is this better, than Asus? Expand - I don't understand the rational for 3rd party firmware, enhancements beyond mfg? Why would the enhancement be want able?
Asuswrt has issues which it takes Asus forever to fix, dd-WRT fixs issues fast , new beta 7/8/17 and as mirimir said open-source and additional features then there is this CSRF (CVE-2017-5891) (CVE-2017-5892) (CVE-2017-6547) which has been fixed although Asus took their time about it I moved away for Asuswrt long time ago to Tomato now to dd-WRT
Asuswrt-Merlin builds are customized version of Asuswrt developed by Eric AKA Merlin its better than Asuswrt but under the hood its core is all Asus Asuswrt and has its issues.
Yup I know. I use his stuff because they are based off of Asus. I have never had any issues with running his stuff but YMMV.