Hello!
First, I'd recommend searching through the Forums, since the errors and issues that everyone have experienced will give you an idea of the current state of the Oracle EBS/OTM integration. Several customers have been very forthcoming with their experiences. In fact, we now have a section specifically about integrating OTM with Oracle Applications such as EBS and JDE:
http://www.otmfaq.com/forums/f70/
Only OTM v5.5 CU1 and up are supported by Oracle's pre-packaged integration flows and I've personally worked with clients running OTM v5.5 CU1, CU2 and CU3. CU4 is too new - but I'm sure people will begin moving to it over the next several months. Of course, custom integration is always an option!
Hope this helps
--Chris