Hello,
I have used Advantco rest adapter but never use (or heard of) Kate. But when i searched SDN, i found below link which suggest that it's also quite equipped with all the functionalities to make rest integration successful.
May be u can wait for other experts to express their opinion on Kate
RESTful Adapter for SAP PI - KaTe Kommunikation / Technologie GmbH
Thanks
Amit Srivastava