Pete,
I'm not aware of any client whose been able to use the flows out of the box -- though that's not my greatest concern. Issue resolution has been longer with Oracle than I was used to with G-Log (we weren't great - but we were often able to get quick-fixes out the door effectively).
I've also heard that the integration is being revamped, but haven't been able to get a release date, even from developers. I would guess that it'll be released with OTM 6.0, though (hopefully) something will be out sooner. I would also hope that the integration comes in at the Order Base level, instead of Order Release.
Should you hear anything - dates, specs, included updates - please post back and help keep the community in the loop
Also - please share your experiences with the integration as you move forward - required customizations, requests for improvement, etc. In addition to running the forums, I'm on the OTM SIG Board and will do my best to bring these issues/suggestions to light with Oracle.
Thanks!
--Chris