When comparing Help Scout vs PHPBack, the Slant community recommends Help Scout for most people. In the question“What are the best user support & feedback services?” Help Scout is ranked 6th while PHPBack is ranked 10th. The most important reason people chose Help Scout is:
The Help Scout team responds to any questions, concerns and suggestions quite quickly.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Fast and helpful support
The Help Scout team responds to any questions, concerns and suggestions quite quickly.
Pro Actively developed
Help Scout is constantly being improved with features being updated and new features added on a regular basis.
The developers do a great job of acting on user suggestions.

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 mobile app
For anyone who may need to work on the go, keep in mind that Help Scout does not currently have a mobile app.
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.
