No cloud is considered secure today. It's that simple. There are folk that want to assure us but most of them have a cloud to sell. Read about what happened to Lavabit and see why you can't have an locked up for sure cloud today.

That said, all seem pretty secure but the fact that our governments mandate backdoors means that such is open to security issues.

-> On top of that, here's another proof it's not secure. Let's say your site/cloud is password protected. If you lose the password and they can reset it for you that means it really wasn't that secure.

As to the other features, those sites let you test drive so you can say yes or no.