I tried every text expansion program I could find for Mac OS X. Eventually, and for awhile, I settled on TypeIt4Me. I found some aspects quite useful and some (including the mangled and/or delayed expansions) quite frustrating.

After giving up on TypeIt4Me, I switched to Typinator and haven’t looked back. Typinator is the only one of the text expansion apps that I have used that allows one to back delete to erase a mistake and then type forward again from that point to the end of the expansion trigger and still have the expansion work.