I didn't waste any time...
Opened up a wedding from last weekend with 2310 NEF files in a single folder. I did the initial edit in PM5. I turned off images without a color rating, it took 1:36 to filter/sort that request. I've been working in that folder off-and-on for 2 days, and that's by far the slowest load time I've seen.
Once that was complete, all other color label sorting was close to instant. Even after restarting the app, it was instant after that.
Arrowing through images is MUCH improved. I'm not truly testing HOW fast it will go, but it feels normalish. Maybe SLIGHTLY slower than PM5 back when I was on High Sierra which was near instant. I'm a split second behind when I arrow through sets of images quickly.
I haven't tested Ingest or anything major as far as processes go as of yet. Just the biggest folder I have on hand and I wanted to give some feedback since the Dev team has been working hard.
Since the last PM6 build/attempt, I have upgraded to 10.14.5.
Model: iMac (18,3 - Retina 5K, 27-inch, 2017)
Processor: 4.2 GHz Intel Core i7
Memory: 64GB 2400 MHz DDR4
Graphics: Radeon Pro 580 8 GB