If you check the developer Q&A videos at Google IO 2016, one of the issues that got discussed was precisely the slow builds.
It is also interesting that they had to re-write the public API in Java for Gradle 3, as part of their speed improvements.
IIRC the gradle daemon made things competetive if not faster, though it's been a while since I tried.
There is a recent post from the Android team, where they advise to allocate between 2 and 5 GBs for the daemon!
I don't recall it being that dire for my non-Android project, but I don't recall checking my mem usage either...
If you check the developer Q&A videos at Google IO 2016, one of the issues that got discussed was precisely the slow builds.
It is also interesting that they had to re-write the public API in Java for Gradle 3, as part of their speed improvements.