Available for most devices, there's often no reason not to use TWRP unless you have had a Pixel. This changes now. TWRP was released for Pixel devices, nearly a year ago, in November 2016, however, due to the partition scheme, it was a bit tricky to install compared to other Android devices. Obviously, people have still been rooting their devices with improvements slowly but steadily coming for Pixel devices.
One of those improvements is Android Oreo decryption support for TWRP. One of TWRP's many handy features is that it can decrypt data from encrypted devices. Unfortunately, this feature broke upon installing Android Oreo on Pixel devices. Thankfully, the effort of lead developer DeesTroy, this feature has now been fixed for Pixel devices. You can get the fixes by updating your version of TWRP with the following images for Pixel and Pixel XL. Once updated, you should be able to decrypt your device with ease.
In other related news, SuperSU and it's companion SafetyNet hiding app, suhide, have also gotten updates for Pixel devices. The new version of SuperSU can now be properly flashed on Pixels with TWRP 3.1.1. It also lets encrypted devices boot with an unencrypted data partition. suhide has received minor bug fixes.
All of these updates should solve the woes of rooted Pixel users. Now you can tinker to all your heart's content. Are you a Pixel user? Let us know what you think down in the comments below.