Its all utter bunkum
Its all a load of complete bollox. SaaS is a marketing executive's coke fuelled pipe dream and so is 'The Clowwwwd'.
What exactly is the advantage SUPPOSED to be?
Offsite/outsourced infrastructure? - yeah, see how far that gets you, its been an unmitigated disaster for everyone over the last 2 decades. Unless you are a 'Consultant', but those leeches win every time (I should know, I was one).
Affordability? Use the open source gear and stop mucking about. They are mature products now and work more or less perfectly. Besides, this rubbish has nothing to do with open or proprietary code - buy what you can afford and use it well. Dont listen to reps.
Consistency? Pffft, you can kiss that goodbye right from word one. No matter what you do, the owners of the servers will rationalize a way to f**** you up. Be it a configuration change, or an upgrade you dont want (because THEIR security/whatever is at risk - whats that got to do with you?). And I'm not sure where they're going to find this network that stays up forever, I dont think anyone has developed one yet and it sounds expensive due to the tons of fairy dust required.
Server load? Come again? Hardware is FREE now, and networks are just about too.
Why would you need to run anything externally? At all? Ever?
Well.....you wouldn't, won't, and don't.