Young technology is always disruptive. It's competetive but can be ugly for the consumers. Cloud services is in such an condition. What goes into these cloud services never comes out or comes out as useless.
First Google, good thing they support their services on all platforms but migrating out isn't easy as they would claim. Android can't even subscribe to webcal or import entries from exported calendar file, only way is to use google calendar. Fortunatley android contacts application can import from vCard file. Once the depednence on Google services increases, Android & Chrome is an natural choice.
Apple's iCloud is another problem. MobileMe used to sync contacts in address book and the contacts can also sync with Google/Yahoo & other sync services. But with iCloud either your contacts are in iCloud or on local. So one can't sync with iCloud & Google contacts at the same time. Same with iCloud calednar though it supports webcal one has to dig to fing the URL to subscribe in other calendar application. Once you upgrade to iCloud got to use all Apple products. Possibly an deliberate move to annoy people sync Android/GMail with Mac freely. Surprisingly iTunes provides choice to sync contacts from Google, Yahoo & Outlook.
Not much idea with Windows phone, but it'll support sync with Outlook & Windows Live. But MS phone manager for Mac has no option to sync contacts or calendar.
What I actually expected is to choose which cloud services I want and can change anytime as wanted. All this is possibly crippled with these free services. Only ones that work across platforms are paid services like Plaxo or sync products like MarkSpace, SyncMate. And still they are half-baked or don't work seamlessly. iCloud breaks both SyncMAte/MarkSpace contacts sync, unless contacts are moved back to local.
As of me, I had to export contacts from Mac to vCard file and import in Android every now and then. As for calendar tasks, I moved to RememberTheMilk. RTM has both Android/iOS apps and tasks can be subscribed in any calendar application. Buying iPhone makes more sense for the choice it provides in choosing other services.