To me, the weakest part of AWS is always on the technical support - you have no right to create a ticket to them unless you pay for the support fee (as contrast to Joyent /Rackspace/Linode), even you have discovered a bug in their system!
On the other hand, I also agree with @latchkey that SmartOS /Ubuntu is an important factor when we are choosing the platform - for a lot of people, ease of use and larger community is more important than cutting edge features like dtrace and zfs.
To me, the weakest part of AWS is always on the technical support - you have no right to create a ticket to them unless you pay for the support fee (as contrast to Joyent /Rackspace/Linode), even you have discovered a bug in their system!
On the other hand, I also agree with @latchkey that SmartOS /Ubuntu is an important factor when we are choosing the platform - for a lot of people, ease of use and larger community is more important than cutting edge features like dtrace and zfs.