When comparing Get Satisfaction vs PHPBack, the Slant community recommends PHPBack for most people. In the question“What are the best user support & feedback services?” PHPBack is ranked 10th while Get Satisfaction is ranked 11th. The most important reason people chose PHPBack is:
It has been already translated to Spanish and they are adding support for more languages.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Gamification feature
Get Satisfaction offers you the ability to gamify your community and reward actions such as answering a question or writing a review.
Pro Facebook Pages integration
You can use a Facebook application that will integrate Support & Feedback options in your Facebook brand page for your users.

Pro Multi-language support
It has been already translated to Spanish and they are adding support for more languages.
Pro Easy setup
PHPBack is very easy to setup, all you need is a server with PHP5 and MySQL installed.

Pro Open Source
PHPBack is open source, uses GPLv3 license.
Cons
Con Limited customization
There is very little ability to customize the layout beyond adding basic branding (like logos).
Con Small community
PHPBack is fairly young (first stable version was releases in July 2015). Currently the community is small, which may make it more difficult to find help/support.
However, the developer is active on the github page and generally responds quickly.
