There are some nice things about Apple products, but they come at a high price (and I'm not talking about €/$). But still: most of what's hyped as "superior usability" is just superior cosmetics and most of the time much worse usability than any other comparable system... People just don't realize because it looks so nice. (Do you still need to go to the lower right corner of a window to change its size in OSX or did they fix this meanwhile?)

The good thing from my point of view is total integration. Total desktop integration and total integration across devices using iTunes. This is really sexy. I have to admit I love the idea.

But: It only works because they force end users and developers into certain constraints. You could have the same amount of desktop integration for, say, contact data if somebody would force all GNU/Linux developers to only use the evolution data server and, maybe, telepathy on top. Would be convenient. But we'd loose all the freedom and flexibility.
Same with sync services: There are many services out there that each do a part of what iTune does. Maybe if you're clever you find a combination that does most of what iTunes can do, and still you'd miss a lot of features. So would be want iTunes? No. I wouldn't want to be forced to use one way of data exchange. I want choice. I want to be able to use separate services for business data and private data. I want to do it my way.

So, as sexy as all this Apple-style integration is, I wouldn't want it as long as it takes away my freedom of choice. So what we could do is get close... at least offer frameworks developers can use, offer an application store they can upload their projects to. But this is already happening. There is a consistent framework for contact data on Maemo - only developers don't use it (or does Gizmo access the EDS? No!). There is the "Extras" repository - and while the situation has much improved since my last rant, still there are packages that are not in it. So, that's life. Freedom of choice also means freedom of choice for those who don't want to make their own product more sexy. I'll gladly live with this as long as the alternative is an Apple-style closed universe.