I would say that I'm surprised by some of the comments about price, but I'm not. I've read too many opinions from people who say that $10 is too much for something that makes their life much easier. Ever take a cab when you could have walked or taken a bus? Ever gotten fast food instead of making lunch yourself from groceries? Come on, people!
Anyway, this utility enables me to do something VERY useful: save my SMS conversation, my call log, my Notes (without using Apple's Mail.app), and more. I paid $10 gladly.
I've had a few issues when MSB tries to read the data files created by various third-party apps (especially the AT&T app - not sure what was wrong with it, but I bet it was AT&T's fault). When I've emailed the developer, he was very responsive and helpful. He handles my complaints professionally and has resolved the issues I had. What more can you ask? MSB has to deal with many different file formats in the iPhone backup and the developer has pointed out that people are reluctant to send him their files so he can see what went wrong (I was at first, but have come to trust him).
Anyway, this is a VERY useful application and there are no good alternatives that I am aware of. So, the question is whether backing up your conversations, call logs, and more is worth $10. If the answer is "no," why are you an iPhone owner? You're paying how much per month to create those messages, and yet don't care about saving them for the future?