The service provider has a reason to make it easy to use their services on any hardware. Hardware provider has a strong reason to not make it easier to access their services from third party hardware. So why not go with the company that doesn't care* how you access them, especially in the context of your data? It is repeat of why Kindle is much more successful than iBooks.

*Google is blurring the line a bit with Android, but still makes their real money from their services.

I think you are spot on describing one side, but it's worth looking at the other side. How do these companies make money? For the hardware company, that's easy. For the service company, that's monetizing your data. Apple cares more about how you access data, but less about the data itself. For Google, they don't care how you access your data so long as their algorithms also have access.

The Kindle example veers off slightly from Google because people pay for their ebooks.

Im much more comfortable if the company Im paying makes money on the hardware I buy and doesn't make money on my data.

What makes you think Apple won't make money on both?

With iCloud Apple will potentially make money off the service because some customers will pay cash for extras (more space, more services, etc), but that's it.

Apple is a weird company because for all the eyebrows they raise with talk of closed systems and hubris and whatever else, they primarily make their way in the world by selling goods to consumers for money. The infrastructure enabling that is a crazy thing, but the heart of it is pretty old fashioned.

At the Keynote Stece Jobs had a bulletpoint "no Ads". I like that.

I do think my data is safe and private at Google (not so much trust in Yahoo and Facebook), but I am certainly looking forward to iCloud. Example: Gmail is a really good and free email-provider, but it also really sucks if you go through times that suck like a break-up and the adsense advertising is mirroring the unpleasant mails stored in your inbox.

Exactly

If you aren't paying for the product you are the product.

Exactly. I've bought many kindle books but have no interest at all in buying through iBooks. I do have several Apple devices now but I don't want to be chained to them forever.

Google also makes it fairly easy to export all your data if you decide you want to pick up and move.

Exactly what bits of iCloud will be hard to export? Music? All DRM-free now. Photos? Sync to your Mac/PC and copy anywhere? Mail? IMAP. Calendar? Caldav. Documents? Sync to your Mac/PC again…