I dont have the highest spec unit, but I will give my .02
33.7 SNR, 72 LP, EBI .8, HALO .7, no blems
Compared to Omni 4-7 tubes I have tried I'd say the ability to read license plates due to a combination of autogating, low halo, and high resolution is one of the biggest differences. The others lacked clarity of the dark numerals or the whole plate bloomed out from reflected light. Also, there is a distinct reduction in laser dot bloom with mine. Compared to units with halo over 2.0 its a massive improvement.
Even at 72 lp, I feel I could see and use more resolution if I could get it, but not much more. I use mine over my left eye, which was laser corrected to 20/20.
The only time I could use any more SNR is indoors or under a forest canopy, not out in the open on 99% of nights.
I could only use less EBI when I use something that restricts the light coming in like my daylight filter or Matbock Tarsier. I dont use mine for astronomy.
Even less halo would be better, though I dont know what real world ability it would offer me.
I could never justify buying a non autogated tube from the used market. Manual gain on the other hand is just nice to have but I could live without it.
No blems is nice but a blem in zone 3 wouldn't bother me much at all. A blem in zone 2 would be annoying. A blem in zone 1 and I'd not even consider it.
I think if you could get more and more SNR with lower and lower halo and EBI, the best use would be to cut down your objective aperature size to give better depth of field so you never have to use the focus.