This is the best tool I have used till today as it allows us to handle automation in variety of ways. It has lots of features which are bundled together in a single package (e.g. OTM, OFT).
We can use the same automated test script for functional testing. Lots of features are there in it. Best tool for automation on Siebel Object.
In the past one year, I have worked on the upgraded version of OATS 11.2 and its has some good features with includes automation API for Peoplesoft automation, good log management and improved version of interface.
Although it has few issues with Oracle Siebel Object Identification which is sorted by Oracle by providing patch. I will update you further in the coming months.