A few months ago I migrated my personal website (a single page with a bunch of links served by Sinatra) from Heroku to AppFog. I did it because Heroku service has one big limitation: you can’t point a root domain to a Heroku app. Actually there are some workarounds to do it but Heroku discourage them.
AppFog is quite different from Heroku. It allows you to point your root domain to their app (see blog post and docs about that). It doesn’t use GIT for deploy, it uses a command line tool called
af who transfers your code from e to the cloud and perform management operations (actually really similar to Heroku toolbelt).
Setup is done using one of the available Jumpstart, a ready-to-go scaffold for your needs. There are jumpstarts for Rails, Sinatra, Django, WordPress and more. In addition you can choose several add-ons (many of those are also available on Heroku). The free plan offers you 2GB of memory with no limits. It’s enough for personal use.
Another advantage is the lack of idle. Heroku Dynos goes idle if you app isn’t accessed for a while. My site has 5-6 accesses per day so it’s idle for each request… AppFog seems not affected by this problem, probably works in a different way.
If you website is small and has low traffic my advise is to use AppFog.