To me they feel very close to a black rubber, at least on the flippers. Drop catches are much easier than on fresh reds, and dead bounces are possible, but weaker. I use them anywhere that the action of a regular black rubber would work, but I'm hesitant on EMs, or on modern machines that already have long playing times. Not like it's hard to swap rubbers on EMs anyways.
Titans will generally make things easier, particularly for highly skilled players. If you are accustomed to playing on games with real rubber, you will notice ball-spin and bounces that move the ball in surprising ways. Most casual players will never even think about it.
To be clear, this is meant to be an endorsement! I use Titans exclusively on my restores (except for EMs), and have only had good experiences with gameplay, ease-of-cleaning, aesthetics, and customer service. Xenon looks great with all translucents! All of my machines are on route, and I consider them to be a solid long-term investment, particularly in my own free-time.
I still use real rubber on all outlane posts. All of the synthetic post rubbers I've tried are way too bouncy for my taste, often auto-saving a ball from an outlane where skillful nudging would usually be required. I would be very interested if they ever offered "deader" post rubbers or softer flipper rubbers, but at the end of the day it's a great product and everybody should buy lots of them.