Appengine experiance
Appengine definitely does meet the characteristics of NIST. All of them, including elasticity and measured service.
Reliability - I've never experienced a local server/s better than appengine.
Scaleability is achieved by statistics - more independent applications on large infrastructure, same rules as any statistical service model.
In-house: in the first place looks like the obvious solution, but the business must maintain power back up, remote backup and all those issues related to business continuity, and by the end of the day it's a nightmare for all the remote users. On the cloud, each user is remote and business continuity is assured.
My conclusion is that if you are not IT oriented company, MYOB (mind your own business) and move to the cloud.
