TBH its personal preference. I've heard nothing but good things about both attys but I've only got to mess around with the Omega. Hopefully today I get to see the Origen because my buddy is supposed to pick it up later.
Omega Positives:
1. LARGE screw heads. Big plus for me specifically because I build on the posts rather than holes. So I love the large screw heads on the Omega.
2. AFC is actually pretty good. The holes are 7/64 wide open. My drippers have 7/64 holes on them (before I had /32) so it's nice to see AFC that goes a little bigger than 3/32. Oh yeah, you also get the choice of doing dual and single air holes which is nice.
3. Deep drip well, 'nuff said about that.
4. 22mm base (same with the Origen) so it'll sit flush on most mods.
Negatives:
1. Holes are off to the side. This is the biggest (and only) issue for me. I'm always doing center post builds and my holes are directly in front of the coils. I naturally build center post on the Omega so it doesn't perform as well since the holes aren't in front of it.
2. No post holes. If you're not used to building on the posts rather than holes, it MIGHT be difficult to get used to. I say might because the large screw heads make up for not having post holes and it also makes building easier.
3. Not much room to work with. Because of the AFC and the deep well you don't have much room to work with vertically.
From what I've seen on the Origen, there aren't that many down sides to it.
I BELIEVE the biggest air holes on the Origen are 1.8mm, the Omega is 3mm. Juice wells are deep and can fit 20+ drops (so I've been told). I've seen some horizontal coil builds and a lot of people are liking it more than the vertical builds. The main downside that I've seen about the origen is the fact that it uses an allen key for the negative posts rather than the usual Phillips.
Hopefully my little input has helped. TBH I think I'd rather go with the Origen even though I've never actually had one in my hands.