PP team just released a jailbreak for iOS 8.4!
Our advice will be to wait for @saurik oppinion before jumping on. As usual, Cydia Substrate might need an update.
You can download PP jailbreak for iOS 8.4 from here:
download: PP Jailbreak for iOS 8.4 (B)
description: PP Jailbreak for iOS 8.4
Edit: Seems that PP stole TaiG`s jailbreak and adapted it to work for iOS 8.4
TaiG will release the jailbreak for iOS 8.4 in about an hour, so you might want to wait for them!