When comparing FreeBSD vs Haiku, the Slant community recommends FreeBSD for most people. In the question“What is the best operating system for a developer?” FreeBSD is ranked 5th while Haiku is ranked 8th. The most important reason people chose FreeBSD is:
Ports provide a wide collection of software which are easy to build, install and modify. They contain recipes and patches to build various software, so you can simply run "make && make install" to build and install the software. You may also keep local patches and it would be picked up automatically. It also allows you to use the latest software even if you are not using the latest version of the operating system.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Powerful ports collection
Ports provide a wide collection of software which are easy to build, install and modify. They contain recipes and patches to build various software, so you can simply run "make && make install" to build and install the software. You may also keep local patches and it would be picked up automatically. It also allows you to use the latest software even if you are not using the latest version of the operating system.
Pro Batteries included
Base system contains basic developer tools, including compiler, debugger and system utilities.
Pro Jails mechanism
Jails allow for partitioning a system into several independent "mini-systems", a feature not found in many of the popular OS choices.
Pro Stable updates
Pro Great philosophy
FreeBSD won't change everything from a version to another, it tries to keep and maintain old tools as long as possible, and won't replace half the system every two versions like GNU/Linux distributions such as Ubuntu, Arch or Fedora does. everything is stable and also pretty minimal. FreeBSD is designed for performance.
Pro Very fast
Pro Beta has been released
After about 6 years since the alpha version, beta has been released on Fri, 2018-09-28. Check here for release notes.
Pro Only need 512mb ram
Pro Stability
Pro Runs perfectly on old Hardware
Cons
Con Pathetic third-party application support
Need to run Photoshop? No luck. Even most software that's portable to Linux will have a hard time running on FreeBSD. You're stuck with ONLY running the free software.
Con Inferior driver support for workstations
Lack of drivers for some modern personal devices.
Con Not for beginners
If a user needs an easy way to navigate around the filesystem, a text only Unix-derivative is not his best choice.
Con Very shallow desktop support
Con No one uses it
It's a very niche OS that no one uses.
Con Unfinished
It's still in beta and quite unstable. Making it unsuitable for developing applications of any kind.
Con Language support is terrible
Con Small community
It is important when developing to be familiar with tools that other developers use. You can make any utility in any language you feel like, but if it's in an esoteric language that no one can read targeting a small platform that no one uses, then it was just something you did as a hobbyist, not as a developer.
This is not to say that Haiku isn't a great operating system to hack around on. Just don't delude yourself into thinking you're doing it to get familiar with tools that you need to know to be a better developer.