I use sdkman to install each and every Gradle release or RC in several different environments (all Mac or Linux). I have not had any issues with any release so far.
Since your post, I’ve uninstalled, flushed, and installed Gradle 2.14.1, Gradle 2.14, Gradle 3.0-milestone-2, and a couple other random versions. I have not experienced any cases where sdkman doesn’t succeed in the install.