Agree with Plink, AFAIK the BAE Micro-Thermal Cores (as I think the original OASYS Cores got renamed) are the best we can buy.
They appear in the following four lines of units:
(original) BAE OASYS Line units (now mostly available as used units, with some being "grey" market)
Trijicon Electro Optics units (Hunter, Patrol, Reap)
N-VIsion Halo and Atlas units
Trijicon Oasys units (Skeet and UTC-xii)
I have four BAE/OASYS cored devices and besides being a thermal bigot, I'm a BAE/OASYS core bigot. But I also have an original XD38A Pulsar and a ATN ODIN.
We moved out to rural Kansas in 2012, so I'm coming up on 8 years. I've been spending an average of 10 hrs per week outside at night over that 8 year period. I started going out with a red lens covered flashlight and a walking stick. I spent about six months out in the pastures and the woods (we live in the Flint Hills of Kansas, so we have hills and crick and woods as well as pastures) with just red light and stick. That experience dramatically increased my comfort level with being out there at night. I love it. I find it very relaxing and stress reliving compared to my prior 23 years in the corporate technology worldin the CA Bay Area.
Then I got a crappy ATN PS-22 NV clipon and then finally in 2014 my first thermal, an Apollo 384, and so on it went from there.
Around here I've seen temps from -20F up to +110F and humidy from 20 up to 100.
The BAE cored devices can definitely see the terrain better than the lessor capable cored devices, such as the pulsar or the ATN. And even more so at longer distances out beyond 300yds. I can see cattle out to 5,300 yards with thermal from atop one of my hills.
But either the ATN (pre chinese ATN) or the Pulsar or the BAE cored devices all can detect critters out way beyond any distance I would shoot them (500yds max for shooting yotes at night). So they all work for detection.
So as to image and PID and I've made these points before. This is NOT a linear construct. Is it NOT the case that one unit is always better than the other. Further more, thermal has more knobs than NV. The operator is a bigger variable in my experience, than the difference in the units. There are is no "magic" setting you can find that optimizes thermal image for all conditions, ,even on a given night.
Nuc-ing, inverting, adjusting contrast (a.k.a. gain) and brightness as well as digital magnification are all components of optimizing image at the moment and hence getting PID on smaller critters at greater distances in less time. Given enuff time, PID is almost always possible by watching the critters move. But, PID can be done faster by optimizing the image for the moment. Operator experience with thermal again, is the primary variable in my experience. I've PID a yote at 500yds with the ODIN while I was rolling on my 4 wheeler. The yote was moving up a hill as well. Now could I do that again? IDK, but it happened once.
Stating "the distance at which PID is possible" is almost a non-starter question. It depends on the conditions, it depends on the experience of the operator. Those are bigger variables than the differences in the units themselves.
(EDIT: Operator experience doesn't just affect image optimization, it also affects PID. When I first started going out at night I couldn't PID worth a sh^t. It takes time to watch the critters under thermal and learn how they look and how they move etc. It doesn't take 100 years ... and for some the time might be much faster ... and it isn't like you climb a cliff one day ... it comes on you gradually. But I'd say after 2 years I was 5000% better at it).
That said the Chinese and nada/chinese thermals I've had did not hold up in the field. Not reliable. So that's a different sort of issue, but a key one none the less.
And units with a fixed focus at short distance are also more difficult to PID weith out beyond 100yds, though you can still detect with them out to 600-800yds on many nights.
As an example, and this was about 2 months ago (and the details are in my night shooting thread) I was out in the rain at night. It had been raining for several days, the terrain was drenched.
I had the skeet the utc-x a 14 and a coti. From my setup position with those NODs I could essentially see zero terrain. Looking in a few directions I could barely make out the tops of the trees against the sky. That's the last to go. But with the NODs I was essentially blind. Yes even the vaunted UTC-x could see nada. My mk1eb could see more than any of the zillion $ worth of NODs I had out there at night. Now, could I see the critters ? Yes. But could I see any terrain ? No. I navigated by compass and by the bare few places were I could see the tops of the trees against the sky.
So no matter what fancy gear you have, there will be conditions in which the gear does not work.
Also, I grew up in Florida, so I'm familar with rain.
But for detecting and PIDing the critters at night, in all manner of conditions or terrain, thermal trumps NV except in a tiny few conditions. Snow is one. NV is fabulous in snow due to the luminosity of the snow. But thats for seeing the terrain, thermal can still see the critters better.
