I'll try and keep this brief and concise (which is tough for me

) but remember, this is just my opinion and opinions vary. These are in no particular order.
1.I like the ergo/feel when the display enclosure is mounted on the grip better than when its mounted on the "S" rod.
2. In auto-tune (AT) mode, I like the way the threshold comes in earlier in the sensitivity range with the Omega. It gives you a wider range of sensitivity settings where threshold is present. Note they both have excellent depth in AT.
3. Also in AT, for those times when I want to run a threshold for extended periods, I really like having the option to change the pitch of the threshold. The Omega has this feature, the Gamma does not. I use this all the time on long days of AT with the F-75 and T-2 which both have a MUCH wider range of adjustment I might add. It's just nice for audio fatigue and having options for which pitch your particular hearing "hears" things better for .
4. The Elliptical concentric of the Omega actually slices and dices (read separation) slightly better than the round concentric of the Gamma. I set up three targets on top of the ground each spaced 2" apart and tried to separate the good target out when it was on the end as well as in the middle. I could do it both directions (back and forth as well as up and back) with the Omega stock coil but only one way with the Gamma coil. Of course sweep speed was somewhat important and coil proximity was critical, but that's the way it shook out.
5. Knobs!

Now I can't complain at all about the Gamma controls and interface but I guess I just have that bit of "old school" fartsky in me that likes to reach that thumb up there and turn something. Really not important butjust a preference.
6. Omega sensitivity adjustment is in single digits all the way through it's range whereas the Gamma adjusts in 5 number increments until you get to 90 and then it goes into a single number adjustment. Again, probably not a big deal but I prefer to have the ability to adjust in single number increments all the way through the range.