i work in a company and we are hosting with amazon ec2, we are running one high cpu instance and two small instances.
i won't say amazon ec2 is good or bad but just will give you a list of experiences of time
reliability: bad. they have a lot of outages. only segments mostly but yeah...
cost: expensive. its cloud computing and not server hosting! a friend works in a company and they do complex calculations that every day have to be finished at a certain time sharp and the calculation time depends on the amount of data they get... they run some servers themselves and if it gets scarce, they kick in a bunch of ec2's.
thats the perfect use case but if you run a server 24/7 anways, you are better of with a dedicated rootserver
a dedicated root server will give you as well better performance. e.g. disk reads will be faster as it has a local disk!
traffic is expensive too
support: good and fast and flexible, thats definately very ok.
we had a big launch of a product and had a lot of press stuff going on and there were problems with the reverse dns for email sending. the amazon guys got them set up all ripe conform and nice in not time.
amazon s3 hosting service is nice too, if you need it
in europe i would suggest going for a german hosting provider, they have very good connectivity as well.
for example here:
http://www.hetzner.de/de/hosting/produkte_rootserver/eq4/
http://www.ovh.de/produkte/superplan_mini.xml
http://www.server4you.de/root-server/server-details.php?products=0
http://www.hosteurope.de/produkt/Dedicated-Server-Linux-L
http://www.klein-edv.de/rootserver.php
i have hosted with all of them and made good experiences. the best was definately hosteurope, but they are a bit more expensive.
i ran a CDN and had like 40 servers for two years there and never experienced ANY outage on ANY of them.
amazon had 3 outages in the last two months on our segments.
