I've had both...from an end user standpoint, the Omega is a lot easier to upgrade yourself. Less parts, easier to disassemble and reassemble, limited number of things that can fly out and get lost, etc. I've installed their full pro kit in a bunch of P07s and a P01, all of them came out great.
Currently I have a standard P01 that I'll probably either upgrade myself or send to Cajun for a workup. It's a bit more complicated and takes a bit more practice to disassemble and reassemble. There's a small spring that's really easy to lose or damage when disassembling/reassembling, which can complicate things as the gun is essentially down until that spring is replaced. There's more parts involved that could use some touching/tuning if you decide to go that route yourself. Having said that, the standard innards are well understood, have been in production since the 70s, and are basically bulletproof. Any issues are well known and documented, and it's a very reliable system.
I initially liked the Omega setup because it let me switch between safety and decocker carry. As time went on I found I didn't like the safety on the P07s (too small to reliably hit on the draw), and while the P01's safety was nicer...I found that I preferred to carry decocked anyway. So the ability to swap between safety/decocker was kind of not needed. But, the decocker on the Omega series guns is kind of fragile. I've broken one. There's a little nub on them that's pressed and glued on, and I've had that break off. It happened to me on a gun with less than 500 rounds through it, though I did do maybe 2k dry fire and decock/reload reps on it, maybe more. That makes me a little less sanguine on the Omega setup, tbh.
So if you're going to go for a decocker only setup anyway...there's no real downside to the standard P01, especially if you're buying it already worked up by CGW. If you're not sure you're going to ever want a decocker gun and prefer a thumb safety, I really like the one on the P01 Omega to be honest. The factory thumb safety on the safety P01s leaves some to be desired IMO; too slick for me. They can be replaced with larger versions, but they need to be fitted.
Really, it depends on what your end goal is, I guess. For the most part, there's little reason to switch from decocker to thumb safety or vice versa, barring some real specific circumstances (finger/hand injury that prevents the full range of motion needed for a DA pull, or a severe case of arthritis, things like that).
