If you have any typing skills whatsoever you're better off disabling predictive text on your smartphone. Ever since I've killed that cursed interloper, my texts have been much improved. Occasionally, I'll mistype something and have a minor typo. But, that's a fuckton better than having the piece of shit make wholesale word substitutions that completely strip away intended meaning.
On older cellphones I did like T9 predictive text. It worked reasonably well once I rounded out its dictionary. Most importantly, it was extremely easy to switch to manual entry when it lost the plot.