The new C3.Large is cheaper than M1.Large (and only marginally more expensive than the old M1.Medium), but its CPU performance is roughly twice as good. Swapping over made a notable difference for our web nodes (perhaps 30-40% reduction in server time for the web-facing tier).

C3's instance-level SSD drives are a very nice touch as well.

It should be noted, though, that the c3.large has half the RAM of the m1.large.

Have you tried the new c3 instances?

For the last 2 days i have a script that is trying to allocate a c3 instance with no luck. AWS is having crazy capacity problems in us-east (all zones).

Same here. The ones we've managed to snag have been great, but it has made it difficult to scale out in a few situations when they haven't had the capacity.

We are also getting multiple 500 ServerInternalErrors trying to allocate them.

Good to know - we were salivating and planning to switch from M1 to C3.

in my experince its only us-east-1a that is having problems. i can get instances in b, c, and d no problem.

c3.large instances are awesome!

Keep in mind that your us-east-1a is not necessarily the same as someone else's us-east-1a as they randomly assign the names to reduce the effect of everyone congregating in us-east-1a because it sounds like the best one.

really? thats hilarious. thanks for the info.