The C4s come in multiple flavors, but on the high end, the extra-large versions produce up to 36 virtual CPUs with 60GB of RAM.
(Just a note, the G-Series and C4 Family are not direct competitors. The G-series are meant to be used for highly transactional workloads, like databases, whereas the C4 are compute-optimized VMs).
Carl Brooks, an IaaS analyst at the 451 Research Group says cloud providers are being pushed to offer higher-end VM types by a variety of factors. Some hosting providers offer bare-metal (meaning not virtualized) servers on demand, which can pack hefty performance stats. "Combined with the upward march of CPU and server capacity generally, providers basically have no choice but to add more powerful machines over time," he says.
Google and other providers aren't standing idle either and VM instance sizes aren't the only features providers are sparring over. This month Google announced the beta release of Cloud Trace and Cloud Monitoring, tools that help developers identify the source of problems in their applications and an in-depth monitoring tool to track usage of Google's cloud.
At AWS re:Invent in November AWS threw down the gauntlet of new features.
VMware has some big cloud announcements scheduled for early next month for its vCloud Air platform. Verizon, after a scheduled outage over the weekend, announced that its cloud now supports rolling updates, promising that it will never have scheduled downtime again.
The point is the IaaS cloud market is maturing past its early days of vendors competing on price to distinguish their platforms to now various players competing on more advanced features.