I have 2 macs, an iphone and 2 ipads...how secure is the icloud?
On a scale of 1-10 it's probably a 9.8 or better.
Where do you get 9.8? And what is unsecure to you, that makes up the 0.2 difference?
Just my subjective opinion and could just as easily be 9.98. Almost nothing is absolute in life and since we know of successful brute force attacks in the past (fixed now), phishing scams can still work (user weakness) and we can't foresee all future possibilities.
I still would consider it safer than data on your HD because of all the possibilities. I use iCloud Drive and would not hesitate to recommend it.