You don't have to fully commit yourself to either Android or iOS, and there are many of us that make use of both major mobile operating systems simultaneously. That said, Android and iOS don't always work very happily together. No worries, though; we're here to tell you the best ways to make sure your Nexus 4 and your iPad play nice.
The bad news is there aren't always perfect solutions available—both Google and Apple are keen to lock users into their respective ecosystems as much as they possibly can. The good news is there are plenty of tools and tricks you can use to make a cross-platform life as straightforward as possible.
Thanks to the magic of IMAP, it's not too difficult to manage an iCloud email account from the Email app on Android or a Gmail account from the Mail app on iOS (or a third-party client). If you're primarily a Gmail user, of course, then there are the official apps for Android and iOS that you can take advantage of.
What you can't do right now is create a unified master inbox that stores both iCloud and Gmail messages together (the iOS Mail app and Android Email app both do this, but only on the surface—underneath, you still have two separate accounts). You can't import incoming Gmail messages into iCloud, nor can you use Gmail to send and receive emails from an iCloud address. We'd advise you to choose one as your main email provider, and stick to it.
Android's Email client offers support for extra IMAP accounts.
When it comes to contacts and calendars, prepare yourself for some frustration and hair-pulling. Ultimately you're best off using Google's cloud services as the backend if you want two-way sync with both iOS and Android, which probably isn't welcome news if you have all of your contacts and calendar information in iCloud.
Use the "Other" option to set up CalDAV and CardDAV accounts in iOS.
There are all kinds of potential setups and configurations in this area, but if you already have all your contacts and calendars set up in Google/Gmail, then you're good to go on Android. To add this data to iOS, set up separate CalDAV and CardDAV accounts: Choose Other from the Add Account screen in Settings, select either CardDAV or CalDAV, then use your Gmail username and password with "google.com" as the server.
On the other hand, if all your contacts and calendar information is in iCloud, there's no easy way to get all of this data syncing across iOS and Android devices. What you can do is migrate your data over to Google, though this won't be to everyone's tastes. Log into the Contacts app on iCloud on the Web, select all of your contacts, then choose Export vCard from the pop-up settings menu. Save the resulting file somewhere convenient, then switch to the Contacts pane in Gmail and use the import option from the drop-down menu at the top to get your iCloud contacts into Google's system (you may need to make extensive use of the Find and merge duplicates option at the same time).
iCloud offers some export functions, though a full sync with Android is difficult.
As for calendars, the export process is a little more fiddly. Publicly share your calendar(s) from iCloud's Web interface, paste the resulting URL in your browser's address bar and change "webcal" to "http". Your browser will save the resulting .ics file to disk, where it can be imported into Google Calendar (or Outlook or anywhere else). Alternatively you can subscribe to iCloud calendars from Google Calendar with this Web gadget. In both cases, the transfer of information is one way, and you'll then have to switch to Google Calendar exclusively for a seamless Android/iOS experience.
Let's start with the easy part: music. If you have MP3 or AAC tracks free of any digital rights management or other protection, you can easily get these onto Android and iOS devices alike, and there are plenty of tools to do the job for you. Google Music will store 20,000 of your personal tracks in the cloud for free, and can scan an iTunes library if you already have one set up (unfortunately there's no official iOS app to date).
Amazon Cloud Player is another option for storing and playing your personal audio collection, and this time there are official apps for both iOS and Android to take advantage of. Another option if you already have an iTunes library in place is DoubleTwist, often referred to as "iTunes for Android." It can scan your existing collection and move tracks over to portable devices. Going in the other direction is easier: Simply install iTunes and import your music ready for syncing with an iOS device.
Google Music is one option for getting iTunes tracks onto Android.
Now the tricker aspect: Video. If you've bought a stack of movies and television shows from the iTunes Store, Apple is very keen that you only play this content on its own hardware. It's well-nigh impossible—save for a few shady workarounds—to get these DRM-locked videos to play on an Android tablet or phone.
If you're dealing with unlocked, self-made videos (DVD rips for example) then the picture is a little brighter, and you can get this content onto your devices using either iTunes or DoubleTwist (we'd recommend Handbrake if you need a powerful free conversion tool). If you've bought or rented content from YouTube, you're also in luck—you can access it all though the official iOS YouTube app (though there's no support for Apple TV for the time being) as well as Play Movies on Android.
Your iTunes movie and TV purchases are locked to Apple devices.
If you've joined the streaming media revolution, of course, then your life is much easier. You can spend the time you'll save fiddling around with local files watching extra episodes of your favorite shows on Netflix or listening to the latest album releases in Spotify. Apps such as these and the likes of Hulu, Rdio, et al can sync across multiple devices and platforms and keep all of their available content remotely stored in the cloud.
If there is some kind of magic utility that ports all your iOS apps to Android or vice-versa, we haven't found it. Fortunately, many apps now run happily on both platforms, and will even sync across them—using Facebook, Twitter, Instagram, Skype and the like is fairly straightforward, particularly when all of your data is stored on the web rather than a local device. Many apps still launch on iOS first, but the playing field has leveled out, and most major releases can be found in both the App Store and on Google Play.
There are also plenty of third-party apps that will happily sync your files across Android and iOS for you. Our favorite is still the slick and unassuming Dropbox—it's straightforward to set up and works with a simplicity and lightness of touch that makes some of its rivals look like lumbering gorillas by comparison. In terms of Android and iOS, it can come in very useful for photos and videos: The Dropbox mobile apps can back up every snap and clip recorded on your devices and sync them together into one master stream of content that can be accessed from anywhere.
Dropbox lets you auto-upload photos and video from both Android and iOS.
Evernote is also worth a mention if you're looking to sync notes, documents and other scraps of content. Many of you will already be using it, but Evernote offers excellent cross-platform and Web operability. Microsoft's SkyDrive is also worth a mention as a tool that can keep all of your files accessible across Windows, Mac OS, Android and iOS.
As for document editing, we wouldn't hold your breath for Pages, Keynote and Numbers apps to appear for Android any time soon, though you can download files from these programs through iCloud on the Web as PDF or Office file types. Google Drive, on the other hand, is cross-platform, as is the newly updated Quickoffice for Android and iOS, which lets you edit on the go.
The new Quickoffice apps for iOS and Android offer on-the-go editing.
While it's impossible to cover every individual workflow, device and OS configuration, we hope that the pointers above can put you well on the way to getting Android and iOS working happily together. If you've got tips from your own setup that you'd like to share, leave them in the comments below.