Honestly im surprised its not talked about more since there is a big push for personal privacy when it comes to data. Encryption really is a pain in the ass to work with on android. Figuring out how to switch or update custom roms while encrypted will drive you insane. The easiest way is to just odin back to stock and start over, but that requires a computer anytime you need to flash anything.
I recently was trying out one of the 4.4.4 GPE roms and turned on encryption. It worked great until i started missing touchwiz and wanted to go back to HyperDrive TW. So the journey began...
First of all, i backed up everything to external storage since i knew everything on the internal storage would have to be wiped. I loaded the phone into recovery mode (using TWRP) and tried wiping, but all i got was a bunch of "Failed to mount" errors. Fine. Got the same error when trying to factory reset or wiping /system, /data, /cache, and anything else. Tried formatting to different file systems and then formatting back to the original but no luck. Fixing permissions didnt help. I just kept trying everything available multiple times.
Eventually it started wiping everything except the /data mount. Well... At least i could install new custom roms. Im not sure exactly what did it because i was just throwing everything at it. Anyways I got it to install, and booted into it. Nope.
Now it was saying I needed the password to decrypt the internal storage. It would detect wrong passwords fine, but as soon as i put the correct password in, it would allow me in, show the green android encryption picture, then blank screen. I thought it was just decrypting and setting up my rom but after a few hours my screen was still black and nothing was happening. Pulled battery and went back to TWRP.
I started wiping everything again and again and tried doing everything i could to wipe everything on the internal storage. Again, not sure what did it, but eventually got it all cleaned up and got a new rom installed and could boot into it.
The whole process probably took about 6-7 hours...
I dont even want to enable encryption on the new rom...