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Out of all the large companies (including Google), Apple is the one I'd trust the least with my documents and other data. They've already shown what they'll do if they feel an app is casting favorable light on anyone but themselves, I'll not use their service only to find that something of mine got deleted because it says something Apple doesn't like. I simply cannot trust them anymore.
Funnily enough apple is one of the few companies that you can trust with your data simply due to their target Market. Apples profits come from selling macs and iOS devices, which means that the cloud service is another way like iTunes to get you onto their platform and to stay with their platform. Google on the other hand gets it's profits from ad's which is more likely to lead them to share your data with advertises to increase their revenue.
Some apps being removed have been odd, but also don't count out a lot of apps have had to be pulled due to copyright and other disputes, look at VLC, lodsys etc..
Apple is an advertising company also. In addition, your buying behaviour is possible even of more interest to them than to Google since Apple needs to know what to feed you through the App Store and iTunes.
Both Google and Apple are not to be trusted in any way with you data.
yes your right, i forgot iAd's although i still think out of the two Apple can be trusted more than Google due to the real revenue being the iOS devices themselves, as you said Apple could have a vested interest because of Apps and iAds, however i don't think they would risk it for the sake of making the platform known as unsecure, where i think Google knows they are recognised as a search brand so would push ahead more.
I suppose the general consensus would be if any of our data is entirely safe in the cloud and which of the vendors can offer a guarantee of not touching user data, Im a big fan of DropBox but even they have changed their T&C to reflect exactly this discussion, the access of client data by dropbox.