When comparing UseResponse vs PHPBack, the Slant community recommends UseResponse for most people. In the question“What are the best user support & feedback services?” UseResponse is ranked 4th while PHPBack is ranked 10th. The most important reason people chose UseResponse is:
Currently supports 10 languages, translation tool available.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Multi-language support
Currently supports 10 languages, translation tool available.
Pro Self-hosted option available
It includes unlimited number of users, agents, topics, support of SSL encryption, polls, announcements, and 1 year of support & upgrade. There are also commercial add-ons that can be purchased separately.
Pro Full UI Customization
Easy to configure the interface and the flows
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 No free version
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.