When comparing Zorin OS vs Haiku, the Slant community recommends Haiku for most people. In the question“What is the best desktop OS?” Haiku is ranked 15th while Zorin OS is ranked 33rd.
Ranked in these QuestionsQuestion Ranking
Pro Windows desktop style
The desktop UI was made to resemble Windows 7, but alternative settings are available.
Zorin is compatible with Ubuntu's sizable repositories of Free Software.
Pro Good Selection of pre-installed software
New users may be unaware of what software is available for Linux, but Zorin includes a good selection for everyday tasks out of the box.
Pro Bundles tools for changing the look and feel of the distribution
Zorin includes look changer and theme changer.
Pro Accessibility features
Pro Partial Windows compatibility
Zorin includes WINE and PlayOnLinux to run many Windows applications and games.
Pro Ubuntu got too big
using too much resorces
Pro Installer can set up dual boot
Pro Low resources consumption
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 Runs perfectly on old Hardware
Con Limited desktop styles in Free Version
All free editions only offer Windows XP, 2000, and 7 and Gnome 2. You have to pay $9-10 in order to get Unity (Ubuntu) and Mac OS X themes.
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.