Ranked in these QuestionsQuestion Ranking
Pro Unlimited space
There are no limits on how much data you can upload.
It runs on top of S3 which is very secure, and does not get "all up in your kernel" like Dropbox does.
Pro Mobile, web and desktop apps
You can access your cloud from wherever you want.
Pro Backed by Amazon
Amazon S3 is one of the best network infrastructure in the world and Amazon Drive is probably based on this.