In addition to David's review, another AAS guest reviewer, Julian Grail, has been looking at SMS Chat as well:
"I have been using SMSChat for about a month on a Nokia N97 with the latest firmware. The application installed without any fuss or bother, which is always a good start. I have always been a big fan of Nokia Conversations so I was very pleased to be given the chance to try SMS chat on my N97. I have around 900 text messages on my phone and I found that the first time the application was started, it took a long time to load and sort the messages - this could be down to my hardware, but I did find it frustrating. I also found that the application tried to be too complicated; having many menu options and choices. A good example of this is that when you select a contact from all of your messages, you are presented with a menu of choices which requires another screen press to get you to your SMS conversation - which is the core purpose of the software.
My biggest gripes are: firstly, the lack of built in help, which, given the price, is a big omission; and also the fact that the application does not integrate into the contacts or messaging applications, which means it has to be loaded separately (and on a RAM-restricted device like the N97 this can cause problems) - in fairness to the developers, they may be precluded from doing this by Nokia but it would be nice if this application added functionality to the existing core applications instead of reinventing the wheel in certain areas. Overall it is a nice application, not sure that its worth $14 to me."
You comments welcome on the app or on both reviewers' remarks!