Easiest cloud storage provider for use with Slingshot

I need to allow users to upload images on my site. After a few failed attempts with CFS Im going with Slingshot. As its early on in my project (im pre launch) my priority is easy of use.

Slingshot can be used with a number of different cloud hosting options, whats the best for my situation? Amazon S3 seems to be the standard so I was thinking of trying them out first.