Microsoft OneDrive has the best value if you’re going to pay, at 1TB for $6.99 a month, and that includes an Office 365 subscription. For the most space and versatility without having to ever pay a dime, then you can’t go wrong with Google Drive’s free 15GB.
The problem with such a comparison is that value is translated as price. We all know cost and price are not the same thing. iCloud and Dropbox work with far more applications than any on the list, and it’s usage that matters.
Sadly, no mention of usage.