Wrm57,
Paul and I assessed the Omega in our system shortly after it was introduced. We declined to publish a review.
As others have suggested, if you want an accurate, neutral, lifelike cartridge to form the basis for building a reference class system, the UNIverse is one of the two or three finest we've heard, perhaps the finest to our ears. It's well ahead of any other ZYX (We haven't heard Sutherk's nuded version, which should be fantastic. I urged Mehran to have Nakatsuka-san make that several times over the years, seems like he finally has!). The ZYX which comes closest to the UNIverse is the 4D/Atmos, see our review of that if you wish. The Omega is another animal entirely, and not one we would recommend.
Entirely concur with the comments by Audiofeil and Syntax. The point about needing a superlative phono stage was spot-on, though I'd go further. The UNIverse takes no prisoners with the rest of a system. That doesn't mean it's harsh, of itself it never is. But it delivers everything that's in those grooves (more than you probably know). Any component that can't handle unlimited bandwidth and bottomless information depth at ridiculous speeds will be driven into distortions. Top performing gear from power sources to wire to components to speakers will pay rich dividends.
The good news is, the better your other gear gets the better the UNIverse gets too. Every component upgrade we've done has revealed that the UNIverse is even more capable than we knew. We've owned one or more copies since serial no. 1 and while they're pretty nearly all the same, they keep getting better. :)
The Steelhead is a decent phono stage. The VAC will be better, at least with a UNIverse. We've had both brands in our system. Neither was quite a match for our Doshi Alaap but the VAC Renaissance was very credible and the Phi should outdo that. Enjoy!
Doug
P.S. With regard to Sutherk's speculation about break-in, our experience with 8 or 10 UNIverses is that they settle in very quickly. Even brand new they're never ugly, maybe just a bit tame. That starts to change within 20 hours or less. By 50 hours at most the cartridge has reached pretty much its full dynamic potential.