As you can see, there's a very significant performance penalty that comes with enabling FDE, with a 62.9% drop in random read performance, a 50.5% drop in random write performance, and a staggering 80.7% drop in sequential read performance. This has serious negative implications for device performance in any situation where applications are reading or writing to disk. Google's move to enable FDE by default also may not be very helpful with real world security without a change in user behaviour, as much of the security comes from the use of a passcode. This poses a problem, because the users that don't use a passcode doesn't really benefit from FDE, but they're still subject to the penalties.
When the Nexus 6 review was published, I commented that there were performance issues that weren't present on the Nexus 5 running Android Lollipop. Many users commented that the FDE may have been to blame. Like I mentioned earlier, Motorola provided us with a build of Android with FDE disabled.
I currently don't have an Android 5.0 device but my HTC One 4.4 has certainly taken a hit in performance after enabling full encryption.
What about experience wit