I probably use my texting more than the actual phone. Here's my review: Overall, fairly pleased. The conversational flow is nice.
Gripes:
No way to not display incoming messages unless you lock your phone. If someone txts you something private, POOF, there it is right in the middle of your screen for the whole world to see. I always keep my phone face down on my desk at work due to this. There should be options to a) not show anything, b) show you have a message, but not from who or what c) show from who but not what, d) show both (aka current display).
No MMS!!! To add insult to injury if you do receive one, you can't even use the iPhone to look at it because it's shown in Flash. Grrrrrr!!
When we do get MMS, if it's not obvious, if someone does send you a picture via MMS it should show up right in the current conversation.
No multi-recipient.
No way to forward a message.
No way to delete just parts of a conversation. When someone sends you something private you might want to delete a few lines, but keep the conversation.
It would be nice if it would make multiple conversations for a single person. Eg. If you could put a particular conversation into an archive for later viewing, that would be really cool.
If the person you are texting lives in a different timezone, it can get confusing on the times because you can't always tell if a time shown is their time or yours. Also, not every entry gets a timestamp shown. It would be nice if you click/hovered over an older portion of the conversation if it would popup the timestamp, options to forward it, etc.
The auto-correction is cool, although sometimes very aggrevating when it keeps changing a word to something you don't want! It does seem to have a dictionary of new words you can teach it, however, I've accidentally taught it some incorrect words that I would like to remove, but I can't figure out how to do so.