I was with Amazon S3 because I believed it was a game changer in the cloud business and it had innovated the way how cloud storage was seen today, at least to some extent. They were very product-focused which assured me and they've also got a nice name - Amazon.
S3 is great however it's not the only player in the market today. So out of curiosity, I went with RackSpace CloudFiles platform.
Very similar to S3, CloudFiles offers only to store files and data but has no such abilities as computing power (PHP, Python, etc.) or database queries. However, after giving CloudFiles a try, I have to say they are very distinct products from each other.
1. RackSpace has everything in the control panel, in one portal whereas Amazon AWS has support, billing, API information all outside of the primary administration panel. This makes more sense as I can get anything I need just a click away. It has a smoother learning curve for new customers.
2. I then create a "container" (equivalent to a "bucket" in S3) to upload and store my files in. I'm allowed to name the container however I want - a huge improvement over S3 because at S3 people compete for the names as they are all in the public name space.
3. CloudFiles distributes all the data and content in your container via a CDN (by Akamai) that's distributed across the Internet whereas Amazon S3 requires a user to choose ONE data center location for a given bucket to be provisioned. This is a great advantage over S3 if you have a geographically scattered worldwide audience because at RackSpace the data you have in the container are all internally cached across the CDN throughout the world, ensuring rapid content delivery to all users regardless to their locations. Although S3 has CloudFront CDN as an add-on, I find RackSpace to be much simpler simply because it's a built-in option.
4. As of now, I personally find that RackSpace Cloudfiles is a bit more expensive than that of Amazon S3, because Rackspace doesn't have an affordable version (reduced in redundancy) of CloudFiles as "Reduced Redundancy Storage" of Amazon.
5. However, RackSpace is actually more cost-effective considering they have the worldwide CDN service by default. S3 on the other hand provides it at additional charges. This becomes even better when Rackspace eliminated all the fees that were previously charged for per-item upload and downlod, leaving their pricing much more clearer.
6. The support from RackSpace is absolutely superior over Amazon S3. While it seems almost impossible to get in personal contact with Amazon, Rackspace offers insanely rapid support. In fact, all my questions have been clearly and well answered within minutes of talking to their online chat personnel.
To conclude, despite the few complaints I have with them, I am confident that RS Cloud Files is or is becoming a more appealing service for individuals and businesses alike. Both them and S3 are solid products. Try both to know for yourself. I never regretted my move.