I just updated my Galaxy S4 to Android 5.0.1/Lollipop. I don't like to use the drop-down spell check/autocorrect box; I prefer the one built into the Google Keyboard that displays as a line of suggestions above the keyboard. The drop-down displays over that line so I have to back out of it to tap a suggestion.
I had it disabled on Android 4.4.2/Kitkat and cannot figure out how to turn it off in 5. I've toggled all settings under Google Keyboard and Samsung keyboard to no avail. The only way I could find to disable it was to force close the Samsung keyboard, but unfortunately I can't permanently disable it.