I am posting this outside of my ongoing thread about my adventures with the High Sierra beta to be sure it is noticed. Due to computer problems I got a new 13" i7 MacBook Pro and elected to install the High Sierra Public Beta. I noticed a significant change in the installation process.
In Public beta 1 (Developer beta 2) the installer offered the OPTION of MacOS Extended format or APFS.
There is NO OPTION in the current beta installer, APFS is installed automatically. To verify this was not a function of an SSD vs Rotating Rust, I erased an external HD to MacOS Extended (Journaled) a.k.a. HFS+ and installed High Sierra on it. With no question and no notice the installer reformatted the drive APFS.
It appears that the PREFERENCE of APFS for the boot drive has become a REQUIREMENT. Whether this will be true in the final version, I don't know. At least the conversion is non-destructive.
FWIW other than an initial glitch with Time Machine and encryption, I am quite happy with APFS. My tests showed it to give noticeable better performance than HFS+ even on rotating rust.
