Just like Mac and PC users, users of different mobile platforms have different wants, needs and characteristics and should be treated as such. Most cross-platform apps take a one size fits all strategy, assuming that if they find a successful design on one platform they can just copy it on the others. There are many problems with this strategy, but the most important thing is, if you employ this strategy you are leaving value on the table and not properly serving a huge part of your audience. So the question then becomes what really is the difference between users and where do their different expectations and needs stem from?
Each platform has a baseline experience, with guidelines for how to develop applications and standards that are set by app developers over the course of years of building for each platform. On average if you look at a group of apps on the iPhone they will have a certain look and feel, while a group of apps on Android will feel unique with their own visual cues and Windows Phone apps will have yet a different feel. Clearly not all apps follow the platform standards, take Clear as an example. It looks nothing like a typical iPhone app. That is less important than the fact that the makers of Clear understood that their users needed to be able to use intuitive gestures and clean interfaces to manage and get through their task lists quickly and easily.
Tinkerers vs. It's Just Got to Work
The base of users for Android tend to be tinkerers, they want to customize as much of their experience as possible. This differers from the base on the iPhone who prefer an experience that just works. They want their apps to be smooth, intuitive and react as expected in every situation. If you've ever put an iPhone in the hands of a Blackberry user and gotten a strong negative reaction it is the exact same principle at play. The reaction happens because a Blackberry user has developed deep expectations and has specific needs about how interactions, specifically those around typing should happen. So understand the persona of your users and why they chose the platform they did.
Willingness to Pay
This difference has probably been talked about the most over the past few years, with lots of reports showing Android trailing iOS in revenue while dominating in device market share. There have been many explanations posited for this from the types of apps that are developed to the ease of payment on the iOS platform. In my opinion, the main reason Android apps convert less value from their users is because the vast majority of Android users bought their phones because they were the least expensive alternative and as such have less ability to pay for apps. Of course the slick devices like the Samsung Galaxy line of phones get the most attention, but the devices that give Android their dominant market share are all of the super low cost devices that are in effect replacements for feature phones. Generally these devices aren't even running the most recent version of Android and don't have all of the features that many apps are built to support. An upcoming article will discuss this particular problem of device fragmentation in more depth, as it is a very real issue for Android and one that is potentially creeping up for iOS. But the important thing to note is that users willingness or ability to pay is definitely not equal across platforms.
Know The Mobile User
Overall, the platforms and devices are just plain different with different reasons that customers buy them, and different ways in which people want to use them. To be successful, on any platform, you need to understand these intricacies of the user base. You need to know if they are the tinkerer type and offer them ways in which they can customize the look, feel and functionality of their apps. Or you need to know that they bought their device because it was the cheapest phone they could find and plan your monetization strategy around the assumption that users won't pay for your app or buy in-app purchases. And you definitely need to know what they have come to expect. Pay very close attention to things like Apple's Human Interface Guidelines and know when it is important to stick to them and when it makes sense to make up your own rules. In the end all that really matters is that you build something that your users want, which may very well not be the same for all users.