Default Cloud functionality question/opinions (Drive, Dropbox, or Box?)

So I'm trying to decide on whether to use Google Drive, DropBox, or Box. I have an account with all three and currently using all for different things (Yeah I know, I'm crazy) but I want to consolidate... One thing that's making it hard to decide is they all surprisingly and oddly seem to be missing a basic feature that would be of tremendous value to me. Unless I'm just doing it wrong, you can't save a 'folder' offline... Now, you can save files offline but not a whole folder at a time. Some of my folders that I need access to offline have hundreds of documents in them and there is no way I'm saving them offline 1by1... Any ideas what I"m doing wrong? Which cloud service do you prefer and why?
Primary Phone: iPhone 5S
Secondary Phone: Nexus 5
Primary Phone: iPhone 5
Secondary Phone: Nexus 4
iPhone History: iPhone, iPhone 3G, iPhone 4, iPhone 4S, iPhone 5, iPhone 5S
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