Here's the truth about OMFI.
OMFI was developed by Avid, long before Avid owned Digidesign (1991-2). OMFI uses something Apple developed called Bento. Bento, IIRC, is a container format. Because OMFI uses Bento, and Apple learned from the biggest mistake it ever made with its lawsuit against Microsoft in the 1980's, OMFI was never able to become a standard to the extent that it was ratified and approved by AES, SMPTE, etc.
OMFI, being a de-facto standard, was always subject to interpretation. It did evolve a bit in the late 1990's, and that evolultion is what is known as OMFI type 2. When working with OMFIs using a modern DAW or NLE (by modern I mean software version), always request an OMFI type 2. Why? OMFI type 1 is so different from OMFI type 2 that the code any DAW software uses to open an OMFI has to be for either OMFI type 1 or OMFI type 2, but not both. No DAW software that I am aware of will open both types of OMFI. This includes Avid and Digidesign software.
OMFI only supports mono tracks. If you are using stereo tracks, it will split them up during the export process. It does not support MIDI. It does not support plug-ins. It may move volume automation (I know you can get volume automation from an Avid via an OMFI, but I have not tried it in the opposite direction).
More information about OMFI can be found in an October issue of MIX (from this millenium, can't remember which year).
Regardless of if you own an LE or TDM system from Digidesign, you must pay for the ability to import/export OMFI files. For TDM systems, this is the DigiTranslator option. For LE systems, this is the DV Toolkit option, which also gives you a timecode ruler. As an aside, I've been told that if you save a session on a TDM system with the main counter set to TC, and open that session on an LE system, the main counter will show TC!
So long as you don't change the main counter readout for that session. tutt The last cs release of Pro Tools v6.4.(1), for both LE and TDM, squashes almost every OMFI bug that existed in Pro Tools. The last one was exterminated with v6.9.
I hope you find this information useful.