I kind of lost it waiting on my pre ordered M53, bought myself a used PAM 176 (with sandwich dial) this week. Of course, the first night I had it, I HAD to do a lume comparison to my brightest Lum-Tec, my M49.
I lit both watches up for 40 seconds with a 460 lumen flashlight, then I went to bed. I tried to sleep 6 hours, barely made it to 5 hours. I'm in a lot of pain (knee, hoping to get it cleaned out next week), and we had some good storms.
I woke up several times in the 5 hours. In case you haven't read much about Panerai watches, they're known for their superb lume. The M49 was just a bit brighter than the 176, all 5 hours. Lum-Tec won!
That said, my 176 was just a bit easier to read, all 5 hours, due to having less lumed area on the hands and indices. The M49 has about twice as much lumed area on the hands and indices, and the lume is laid on really thick. The effect is that of all that lume kind of blurring together, if you catch my drift. Take into account my 57 year old eyes, checking the time without putting my reasonably strong bifocals on. I prefer the 176 for readability, it's kind of like an Omega Speedmaster Professional on an overdose of lume steroids.