Very reliable, very well documented if you need how to's, indeed not cheap but would be my number 1 choice if I have to choose cloud services in my next workplace. I had an urgent project and had to learn EC2 from scratch within 2 days, their documentation is so good, I did it successfully- even faster than planned.
Very reliable. Not the cheapest, but you get what you pay for.
My experience with the service was that if I needed something that wasn't already offered by Amazon - this exact solution was announced by Amazon only a few weeks later - just in time for me to use it. Amazon's execution is Very impressive, and they know the community and its needs very well.
What are the pros and cons of each? Which would you choose?