When comparing Android vs Haiku, the Slant community recommends Haiku for most people. In the question“What are the best Operating Systems for x86 PCs?” Haiku is ranked 3rd while Android is ranked 5th.
Ranked in these QuestionsQuestion Ranking
Pro Customize what apps perform what actions
Android gives users the ability to define which apps perform which action. For example, if an Android device has several browsers installed, the user can choose a default one which will start every time a link is for example opened from another app.
Pro Open source
The AOSP (Android Open Source Project) is the software stack for the Android OS. It is led by Google.
The fact that Android is an open source software has led to many custom Android variants. It also is a big assurance of Android's safety in terms of privacy.
Pro Lots of hardware choices
There are about 18000 released devices that run on Android. This means that a user familiar with Android can have a large variety of devices from which they can choose.
Pro Integration with Google Services
For those that already use Google's services, like Google Maps and GMail, Android offers tighter integration with those services than any of the alternatives, and saves users the need to create extra accounts.
Pro Highly customizable
One of the massive benefits of Android being open-sourced are all the modifications you can make to the phone to customise pretty much anything. Some of the cooler things you can do are:
Pro More integrated sharing options
Pro Desktop and lockscreen widgets
Desktop widgets provide quick access to the information you need quickly and access the most. These are available out of the box, and can be developed by anyone. Widgets on the lockscreen have been removed since the Lollipop update, but is available on 3rd party lockscreens such as AC Display and KK Locker.
Built in text to speech is provided by TalkBack for people with low or no vision. Enhancements for people with hearing disabilities are available as are other aids.
Pro Personal assistant with Google Now
Google Now is an intelligent personal assistant available within the Google Search mobile application for the Android and iOS operating systems. It's software that makes your life more convenient by giving you all the information you need at any moment.
Pro Great user experience right out of the box
Pro The most widely used mobile OS
Pro Consistent back button makes navigation easy
Pro Built-in screen recording
Android 5.0.+ supports screen recording via a new api.
Android 4.4 KitKat supports screen recording accessible via an ADB command on unrooted devices.
Pro Cheap phones
Android phones can cost little as $100.
Pro Customizable multiple "desktops"
Can customize the home screens with widgets (not just a grid of apps like iOS).
Pro Security Updates
Android does frequent updates to keep users secure
Pro It's all yours. You can do anything you want with YOUR phone...
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
Con Fragmentation and security flaws due to negligence.
Most Android phones seem to be released on a "Let's release a few software updates until we release the next phone, and never push out an update again." For example, In May 2014, 8.5% of phones were Kitkat, 60.8% were spread out between three versions of jellybean (with bias towards older versions), and the another 20% spread out over ICS, Honeycomb, Gingerbread, and Froyo.
Google no longer maintains Android 4.3 or prior and serious security exploits remain in those versions. Device manufacturers are also taking no action, which leaves almost a billion Android users exposed.
You may also encounter lingering and unfixed bugs, glitches, etc. as a result of the manufacturer's and Google's lack of interest in older versions.
Some flagship phones are well supported into the future, but the fact that your phone won't be supported by its manufacturer and/or Google is a consideration you must make when purchasing an Android phone.
Con Wide variety of phones forces variance in quality
While there are many great Android phones, there are also many Android phones that lack in both hardware and software. When purchasing Android phones, a consumer might want to do some research first - especially when buying on a budget. Not only do you have to worry about shotty hardware or poor quality testing, manufacturers tend to tinker with the software on phones. More often than not this leads to poor performance, unintuitive 'features', slower (or complete lack of) updates, and custom software that detracts from the user's experience.
Con Difficult to use for pro audio
Android M paired with newer devices are getting audio latency down to 20 milliseconds or less, which is great compared to previous Android versions, however is still slower than Apple's 7ms on the iPhone 4S - a 4 year old phone.
There are almost no professional audio tools available for Android because the latency was way too slow for professional audio creation, but perhaps now that Android isn't so far back we will start to see a few options come to Android.
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.