The deciding factors in choosing computer software beyond just money can involve other practical considerations such as ease of use, functionality, reliability, compatibility, support and security. Every software program has to evaluated on its own merits. In many cases open source software is the most cost efficient, but sometimes they have different features from the proprietary software. Reliability will vary from software to software. Some open source software can be buggy in the early versions, which can be true with all software. Technical support for some open source software is at first confined to on-line web sites and newsgroups. Most popular open source software that has gone past critical mass like Apache, Linux and Perl have many books, periodicals and web sites dedicated to them, and they come with extensive help documentation. Other factors in the decision making process include its ability to scale and its capacity for future growth. The overall philosophy of proprietary versus open source can also be a factor when choosing a software program.

Security is a significant issue with certain software. Any program that requires or protects network access would have security issues loom large. For instance, it is a key factor with server computer software, email clients, firewalls and web browsers. Most popular open source software programs are rated as secure or more secure than the proprietary choices. An operating system is the foundation of a computer, so security should be a large consideration when a user chooses a system to run. There is a controversy about whether open source software or proprietary software can produce a more secure platform for a computer operating system. It is important to understand the security risks of any software. In the long term, whether trying to protect a single system or a network of computers, the more knowledge the user has about the software the easier the choice.