The pricing and build-out structure is linear when looking at RAM & disk space, so this may or may not fit everyone's requirements. There is no EBS-equivalent, and load balancing has just been introduced formally into the control panel recently. The persistency is something I've taken advantage of, compared to EC2's ephemeral nature (unless one employs EBS).
As for cloud servers going down randomly, Rackspace Roulette can be tough, and the only silver lining is it provides a good incentive to build (or at least, to think about) applications which work around failure.
There is one other lesser known gotcha which is max RAM capacity per account; I think the default is something like 50GB and if you require more (for burst perhaps), you have to get this amount pre-approved. Apparently this is to safeguard against (accidental) abuse of the Cloud Servers API, but it's probably also a good mechanism for capacity planning on their side. At any rate, I've seen/heard the turnaround to be about a couple of business days.
EDIT: One more note about RS -- resizing cloud servers. It's a great ability to have, but it can be slow. It tends to take longer the more data you have (not too surprising). A good practice is to wipe unnecessary log files before resizing, as I've been told that each resize action actually causes the cloud server to jump to another physical host. Don't quote me though, I'm just on the Internet :)
The pricing and build-out structure is linear when looking at RAM & disk space, so this may or may not fit everyone's requirements. There is no EBS-equivalent, and load balancing has just been introduced formally into the control panel recently. The persistency is something I've taken advantage of, compared to EC2's ephemeral nature (unless one employs EBS).
As for cloud servers going down randomly, Rackspace Roulette can be tough, and the only silver lining is it provides a good incentive to build (or at least, to think about) applications which work around failure.
There is one other lesser known gotcha which is max RAM capacity per account; I think the default is something like 50GB and if you require more (for burst perhaps), you have to get this amount pre-approved. Apparently this is to safeguard against (accidental) abuse of the Cloud Servers API, but it's probably also a good mechanism for capacity planning on their side. At any rate, I've seen/heard the turnaround to be about a couple of business days.
One the flip side, there was a very active thread a while back about how Mixpanel moved away from RS: http://news.ycombinator.com/item?id=1884685
EDIT: One more note about RS -- resizing cloud servers. It's a great ability to have, but it can be slow. It tends to take longer the more data you have (not too surprising). A good practice is to wipe unnecessary log files before resizing, as I've been told that each resize action actually causes the cloud server to jump to another physical host. Don't quote me though, I'm just on the Internet :)