The classic trigger system can be a bit more fidgety. The safety lever detents are small and spring loaded. The Mag Release Spring Screw is staked in place. The Sear Cage can throw you some curve balls when taking it in and out. The decockers Sear Cage is pinned into the frame. The only real tricky part about the Omegas is installing the decocker return spring.
All in all, i am of the opinion that the Omegas are more straight forward to work on but familiarity with either design goes a long way. I have allot less time working on Omegas so i find the need to use reference guides. I have the classic trigger system really locked in at this point. I think i have made just about every mistake that you can with the classics, at least it was fun.