I cannot confirm whether the P01 Omega safety/decocker parts are metal or plastic, but from the photos I've seen, they sure look metal. Especially since the attachment method of the right-side lever looks an awful lot like the 85 Combat. The P07/P09 safety/decockers are plastic.
As far as reliability, there are a lot of rounds through the Omega system with good results. I personally haven't had any reason to question the reliability of either my P07 or P09 and you'll find lots of people on this forum that can attest to the Omega system reliability, as well as to that of the standard system. Aftermarket support is good for both trigger systems and I'd have no qualms about carrying either and I currently have a P01 Omega on order.
The compact is one of my favorite CZs. It's an excellent pistol, feels great in the hand and shoots like a dream. The only modifications I've made to mine are the serrated trigger, VZ grips and night sights and I don't intend to change anything else.
With the P01 Omega, there are some notable differences:
- 4oz lighter
- has a rail
- has an extended beavertail
- straighter trigger a-la P07
- interchangeable safety/decocker courtesy of the Omega system
- much easier complete take down/reassembly
- about 3mm thicker in the slide
- still at least 60-90 days until they show up in the states (if that's where you're located)
If I were choosing between the two, the main things I would consider are A. rail/no-rail and B. wait time. Just my $0.02.