The only reason I gave it an "average" review is that it doesn't support IE7 e.g. if you try to submit a testimonial in IE7 and hit the submit button but have forgotten to fill out any of the required fields the submit button becomes grayed out and inactive. You have to reload the page/form again and start from the beginning--you lose everything. This is also evident on their demo site.
I contacted support and they said they'd fix it in some future version. So, until then, just keep this in mind. Other than that, it works great.
The two test sites, 1.5 & 1.6, I tested it on had basic, custom templates and various plugins/extensions installed. Akeeba handled all of them without a hitch. I even took a backup and installed it on a different server/database. Again, no problem proving how easy it is to migrate to another server. I can now offer a very competitively priced backup option to all my clients for the Joomla sites I've created for them.
A breeze to install and run. Download it now, install it, back up your site, then donate to the author. It's way worth it and will make your Joomla development life so easy.