Here at DZone, we know a thing or two about comparison guides. Dan Sullivan is now working on a narrower guide than DZone's over on Tom's IT Pro. Their PaaS Provider Comparison Guide has an introductory section that discusses how to find the best fit of PaaS, much like the DZone guide's introduction. Then it goes on to individually analyze the following PaaS products:
The unlinked products haven't gotten a completed review yet. Each analysis is less broad than the DZone guide in feature coverage and doesn't provide a side-by-side comparison, but it does go deeper into customizations and pricing scenarios, so I think it's a really great companion to have along with our more broadly-scoped guide. Check it out!