Telerix controls - Desktop automation

Hi All,
Currently, we have a desktop application which uses lots of Telerik controls, I am finding it difficult to automate this, as the test is very unstable and dead slow. Has anyone worked on this before and is there a tool which helps resolve this issue?
We are currently using Ranorex, but I am looking for a tool which can help (opensource as well as paid).

Thanks in advance
Rajee