I'm driving 2 4K monitors and a 27" monitor with my 2017 MacBook Pro...having the same problems as everyone else. I had flickering with a few of the monitors and reseated them and it seems to go away. Comes back intermittently. What is more odd is that when I come out of sleep mode it takes forever for the monitors to come back. Additionally, the display #'s in the OS get reassigned so applications don't stay on the monitors i assigned them to. Very frustrating. I have secondary ports hooked up to my Windows gaming machine with no issue. Very disappointed in this release, wish i would have waited.