A while ago, I wrote about “Faster text entry on a Palm Pilot” and a trial of the TextPlus text entry software. My trial period is over and am still a bit unsure about whether or not I will purchase it.
On the whole, TextPlus worked without problems. It quickly highlighted words and phrases beginning with the letters that I had entered. It was also easy to add new words and phrases to the dictionary; an important feature when integrating into your own vocabulary. I did find a tendency to keep writing and checking to see if my word had appeared. By that time, I could have had it written.
My main reason for not proceeding with a purchase is the rareness with which I use the Palm Pilot for massive amounts of text entry. If however you do, then TextPlus is certainly worth a look.