Recs.
Updated
Specs
Pros
Pro Super cheap with a year's worth of free service
S3 storage costs $0.03 per GB and gets cheaper the more is stored, PUT, COPY, POST, or LIST requests are $0.005 per 1,000 requests and GET and all other requests are $0.004 per 10,000 requests. And with some restrictions is available for free for a year.
Pro Supports custom root domains
To set up a custom domain, Amazon Route 53 has to be configured as the DNS provider with the domain registrar, two buckets have to be created and configured with the name the same as the domain - one including, one excluding www. A more in-depth explanation can be found here.
Cons
Con No SFTP support
Amazon S3 does not have SFTP support, instead the S3 web interface has to be used.
Recommendations
Comments
Flagged Pros + Cons
Pro S3 is better than SFTP and supported by most FTP clients
Most popular FTP clients support S3 natively (Cyberduck, Transmit, and others). S3 is faster than FTP but works the same.
Con Unpredictable monthly charges
Since costs are determined by usage, they vary month by month.