Joyent love micro benchmarks because they allow one customer to grab a lot of CPU in burst, but if you are one of the other customers on the same hardware node, it is better to have a bit slower all the time than high variability like Joyent. Predictability when you run your infrastructure is better.
Also, Joyent will kick you out of their infrastructure if they consider at their sole discretion that they are not making enough money out of you, but this is my personal experience and may not be yours. So basically, they broke the trust I placed in them, I am migrating out at the moment, so take my comment as coming from someone with a bad experience with them.
They have a very decent "private cloud" offer. The feedback is good but I am a bare metal + Ganeti[1] to manage my VMs kind of person.
If you like pure instances, I have also instance running on Gandi[2] infrastructure. My blog made several times the front page of HN and without special caching it handled extremely well the load (in fact, you could barely see the increase in CPU usage in the monitoring graph while seeing a huge increase of the outbound bandwidth).
Another good provider is Hetzner[3]. You need to pay attention to the server you select (ECC memory or not) but then they are reliable (I had a server with them for 4 years or so without a single issue).
In Europe, AWS is in Irland, I suppose it was for tax purpose that they selected this location, but from a latency point of view, this is stupid if you want to deliver packets in the South or East of Europe (and even part of Scandinavia because most of the time your route does IE, NL or FR, and then goes North).
Sorry for the long post... but at the end of the day, do your calculations. AWS is great if like Netflix you scale from 20% to 100% during the day[4] (the hit on the cache gives you how they scale) but if you are a normal shop without day/night activity because you are at global level or so well optimized that you just not need to scale (a single dedicated server with SSD is incredibly powerful nowadays) you simply do not need "the cloud". Just test with 1kâĴ, do a bit of maths, then select the best choice.
[1]: http://notes.ceondo.com/ganeti/ [2]: http://www.gandi.net/ [3]: http://www.hetzner.de/ [4]: http://techblog.netflix.com/2012/01/ephemeral-volatile-cachi...
If curious you may have a look at http://www.youtube.com/watch?v=UBHSz3fOP-4&hd=1 where we mix an eucalyptus private cloud on physical server with AWS.
When you got right down to it, what killed that plan was that you were still using Amazon S3 for storage; the money that we would have saved in CPU/processor time we would be eaten alive with transferring that data back to S3.