If you’re only using one product, i.e. AWS, Slicehost, GoGrid, Rackspace, EY, Joyent, etc, etc, etc, then Cloudkick may not be of use over their integrated control panels.

The value starts when you want to use more than one service to distribute your provider risk or choose the most cost effective provider for a given system role (i.e. Joyent has the best pricing for data transfer, Rackspace has the lowest starting price for $/hr instances, etc).

Cloudkick enables you to choose the provider you want to have as the underlying infrastructure layer rather than having you locked into the platform you started on over “migration fear”. That leaves the providers to compete on overall value of service quality and price.

EC2 is a way better deal overall, unfortunately.

Disclosure: I am a customer of both Slicehost and EC2.

I don’t know the details, but I highly doubt this is as you make it seem. First, EC2 images are more flexible than Slicehost images, Slicehost limiting you to a select few distributions of Linux, so there are going to be incompatibility issues between the two. Second, you can’t really store machine images on Slicehost – technically you can create backups of live instances and build new instances from those, but there isn’t a repository of “templates” to initially create the instances as there is with EC2.

Also, the Slicehost API is quite minimal at this point, and I don’t see how Cloudkick provides a compelling alternative to the internal management portal Slicehost already provides.