I've looked at the Amazon EC2 Instance Types and spotted the t1.micro. An interesting beast - at the time of writing it has 2 compute units (burstable), half a GB of RAM and as much disk space as you can throw at it with Amazon EBS.
I found it quite a pleasant experience, until we launched.
My opinions follow...
These are certainly cheap! Cheaper than many other reputable hosting options out there (offering root level access on dedicated Virtual Machines). The next level up machine only has half the processing power and is 32 bit only for about 4 times the price!
They're certainly quick! 2 compute units of raw power! Provided you don't have noisy neighbours... They held up well in a loaded situation! So whats the problem here then? Notice I mentioned noisy neighbours... When others want resources you will have them taken away from you without warning. It seems the micro's don't have a lower guaranteed processing limit which would have been nice! I've had complete instances fall over and become unresponsive for minutes at a time (up to 20 mins on one occasion). Rebooting will not help you here, as it takes time for it to respond to the reboot, especially when it doesn't have time to even answer a ping! 12,000ms ping time anyone? on a gigabit (shared) network as well.
Don't be fooled. 64 bit is great! But the next level up machine is only 32 bit. You cannot boot any AMIs built in 64 bit micro's in a 32 bit m1.small. This caused me a problem as I had to rebuild my instances in a hurry in the middle of an expensive marketing push!
Clearly the problem is over-subscription. This is mostly evident in the way the micros are mentioned in the documentation. It simply states "up to 2 EC2 compute units burst". What they fail to tell you is there is no minimum. If others on the shared physical host start to have a party, you're drowned out in all the noise.
Don't touch the t1.micros. They will run well in a development environment but they're very bad news for production!
Though to break that rule I'm thinking of moving my current VPS requirements to Amazon, I don't want to pay for an m1.small just yet so I think I'll take the risk with a t1.micro. Still undecided though.
I've heard a rumour Amazon might be removing 32 bit only instance types from their portfolio, this would be very nice! Only time will tell..