lots of +ve reviews but... @amanda, i would personally keep far away from an application by a company / developer called grey shirts yen could give you more insight on this since he is an avid android user
and(est)royed when installing an application i do take in to consideration the parent company / developer. i would not go for an application made by a non-entity like grey shirts. but then again that is just a matter of personal choice.
I don't know about the firewall you have posted and if it works effective without root. To me far more important are the rights an app demands when installed. It is better to be sure to have 'clean' apps installed, better than to have to block apps which should have no internet access. It depends on one's intention why one wants to have a firewall installed. -to protect the OS of unwanted access. -or to control and restrict internet access of an particular app. The first is of a lesser issue since a Linux system is far more secure than for instance windows and the second needs to be decided when installing the app itself. To root a system firstly means to open a 'hole'. IMHO on a non rooted system no firewall is needed, just avoid to use 'free' suspicious apps. But after all it remains always a own personal decision how to use the phone. Everybody has a own idea what is right and what is wrong. I have used avast internet security which requires root in order to use the firewall, though. ATM I don't use any firewall. I have rooted my phone to remove unwanted system apps. Concerning ratings..well actually they do not preserve you that you have to make your own decision, finally. Everybody can rate.....important is to think about before installation.