I looked at that Rightscale link and I think it shows that comparing a very fast moving area like cloud services is very difficult and results in incomplete features matrix. For the unsophisticated buyer, this can lead to misleading comparisons.
For example, Rightscale has "Event-Driven Compute" (sometimes aka as "serverless computation") in the AWS column (AWS Lambda) but that entry is blank in Google Cloud column. However in February 2016, Google announced Google Cloud Functions which is the equivalent to AWS Lambda.
I'd expect a cloud comparison website to update the features matrix within 1 week of the AWS re:invent conferences, the Google I/O conferences, and any press releases.
As for the other comparison Cloudorado mentioned by another poster, that comparison matrix is missing database services like mapreduce, business intelligence analytics, etc.
