There's no question that you need to protect your computer from incoming network threats, and there are plenty of options available. One option, TCPBlock for Mac, functions adequately as a firewall; but its options lag behind other, more popular programs.
TCPBlock for Mac downloaded quickly, but installing it required a computer system restart, which was a disappointment. A readme file contained some basic instructions, but a detailed manual would have been helpful, especially for longtime Mac users not familiar with firewall software. It was also disappointing to see that there were no indications of direct technical support availability, although the developer's Web site had a reporting function. Automatic updates through the program, itself, would have been useful. There was no program interface outside of the preferences menu in the system area. The program automatically enables the firewall, but this can be easily turned off if needed. Few other options existed, but the offered traffic log was easy to use. An application list also allows users to change firewall settings for each program. The program appeared to operate smoothly during testing. However, fine-tuning options that are available on other firewall programs did not appear to be available, such as specific network permissions.
TCPBlock for Mac functions well as a basic firewall application, but lacks the powerful features of mainstream programs.