I will probably go AWS just because of the obvious simplicity of scale, but their pricing is complex enough to make me wonder if it will end up costing me way more than I'd like.
RackspaceCloud is a possibility, but I really dislike the nominal amount of RAM I get for the same money as AWS Small server. But then again AWS might pinch me on ElasticBlock storage.
Anyone?
I've written a fair bit about them on my blog which is in my profile. Though the last update is more about a move to GoGrid and now that AWS has west coast servers we're starting to migrate back.
For overall experience my favourite setup is AWS with scalr.net as a front end. I've used the Amazon interfaces and I just don't find them as nice to use.
As for cost it depends on what you do but in my case its pretty similar across the board for the servers if you prepay(AWS reserved, GoGrid plans). EBS has never been much of an issue cost wise for us either and we had a fair bit of space on there.
One pro for Gogrid at the moment though is the ability to order dedicated servers through the cloud interface. We upgraded to a dedicated server once every attempt to keep latency down on our load balancers failed.
If you have any specific questions feel free to email me or for more general ones ask here.
