When comparing Windows 8.1 vs Haiku, the Slant community recommends Haiku for most people. In the question“What is the best desktop OS?” Haiku is ranked 17th while Windows 8.1 is ranked 38th.
Ranked in these QuestionsQuestion Ranking
Pro Hardware Compatibility
Windows has excellent x86-based compatibility, and has recently announced ARM compatibility as well.
Pro Familiar Windows Interface
As opposed to unfamiliar and purpose-built Linux distros, Windows still reigns supreme for sheer usability and ease of use.
Pro Customizable UI
There are many that can be used to customize the MetroTile screen and add custom tiles. Then, by adding custom tiles you can configure them to open any application or web page that you need. For example: Netflix, HBOGo or Steam.
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
You will need to purchase a Windows license.
Con Resource Intensive
In contrast to many dedicated solutions which can run on nearly anything, running a full Windows install requires decent hardware. This is not a lightweight solution.
Con No one uses it
It's a very niche OS that no one uses.
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.
It's still in beta and quite unstable. Making it unsuitable for developing applications of any kind.