Apple’s HDR is limited - it works with the iPhone 4 back camera only, and sometimes gives underwhelming results.  TrueHDR has full support for iPhone 3GS and iPhone 4, including the front camera on the iPhone 4.  We've been testing out and comparing Apple's HDR since it was introduced, and we feel that you may like TrueHDR's results better.  Of course we're biased :) but we encourage you to judge for yourself.

Below are a few comparison shots.

You can also click here for a 3rd-party comparison from iPhoneography.com