In Support of Cloud Analogies
Personally, I find both the cattle/puppy and electricity analogies to be profoundly helpful in understanding (a) how many organizations and individuals fail to take advantage of the cloud (while still arguing they are "on the cloud" or [as a vendor] "the cloud", and (b) how much further we have to go before we are where we want.
The cattle/puppy analogy is most helpful when demonstrating to people that their "private cloud" (read: VMware in an on-premises data center) is not taking full advantage of the cloud. I don't think it's a particularly helpful way of distinguishing vendors (since, with enough scaffolding and the right application architectures, any virtualized environment can be a "cattle" architecture). But it absolutely helps identify, in short hand, that certain cloud deployments aren't built for failure, and they require too much individualized interaction with servers.
The electricity analogy is very helpful in identifying the compatibility and feature issues we have between clouds. The reason why the cloud isn't like electricity is because so many cloud services aren't fungible (e.g., IaaS, PaaS, SaaS--diferent APIs, different features, etc). That said, cloud storage (S3, Google Cloud Storage, etc) actually can be like electricity, and, in fact, quite a few organizations and vendors do use it this way. We may actually be able to get to electricity for compute, but we're not there yet.