What do you like best?
The managed cloud has just enough features to test, deploy and maintain development, uat/stage and production servers/environments reliable and fast via web or using API and cloud tools. It is much easier to manage your cloud because you are not puzzled by hundreds of thousands of menus and other tools you might never use. The support team in managed cloud is awesome, they always responded quickly and provided the exact expected answers and help!
What do you dislike?
Managed cloud to Public cloud firewall and networking setup could be hard to understand for non-technical people, it is also complicated to manage those rules.
API sometimes returns errors without a clear reason, so you have to re-do the last step (and kill semi-provisioned machines, etc). This is probably a client-side issue, but this is also one of the things I didn't like. RackSpace doesn't pay much attention to open-source tools and libraries (like 'fog', for example), most of them do not support all the features, or are not working at all.
When you have a cloud, you expect to provision it using automated tools/scripts, and open-source tools are very useful here.
Recommendations to others considering the product
This is an awesome, easy to implement cloud solution. If you need a managed cloud, you won't get it wrong with Rackspace Managed Cloud!
What business problems are you solving with the product? What benefits have you realized?
I design, install, provision, support and improve infrastructures for various clients, including e-commerce, blogging, and forums platforms.