Ultimately, iCloud security is a matter of trust between individual users and Apple. As confirmed by industry experts, Apple takes a number of precautions to prevent unauthorized access to user data by third parties, but those precautions don’t secure your data from Apple itself. If you require—or simply want—greater assurance than that, turn off whatever iCloud features you don’t need.
I am really paranoid about privacy issues, but I think the above from Foresman is really an astute observation. No matter the security in place, I simply do not trust Google. The same is not true of Apple, for now.