Good question and I'm probably not the best to answer it, but I'll try.
@kirsh anything to add? < an industry salesperson with a lot of time behind many different models. Here is one of his reviews and he would be a good person to get on the phone with if he is available. He is part of the reason I went with the Hogsters I have.
I posted a First Look video of the Super Yoter LRF a few months ago. I was fortunate enough to test a Super Hogster A3 LRF recently. These both are sample prototypes. Bering is getting close to release and these samples keep getting better and better. Bering will be allowing us to order them...
www.snipershide.com
Some of the cheaper scopes have horrible reputations for quality and customer service. I would stay far away from ATN for example. With limited warranties, it is worth considering
Most of these scopes let you record video, so the internet is full of actual hunts and reviews showing the units. It's worth spending some time watching them.
The sensor is a big part of how clear your images will be, how large the FOV and how high the cost. I believe that larger sensors require larger optics so scope size and weight may go up as well.
A larger sensor is like having a digital camera with a higher resolution. This helps in two ways:
1) clearer image - if the FOV is equal, the image will be twice as clear
2) Better FOV - if the image quality is the same, there will be twice the FOV
3) some mix of the above, more likely the image will be better, but not twice as good, and the FOV will be better, but not twice as good.
Beyond the sensor, not every unit handles humidity the same, some lose image quality when it is hot and muggy. Different batteries and battery life, some can record, some don't, different reticles, etc. This is where advice from someone with lots of experience is a big help.
Just because it is nicer, doesn't mean it is needed. I do not doubt that either of my Hogsters (42mm 384 Clip-on or 2x35mm 384 Scope) would be able to hit hogs at 250yds, but I never tried to shoot something as small as a raccoon at 250yds, so not sure. You may need more magnification or a better sensor to do that. Keep in mind that each scope has an optical magnification and you can also digitally zoom in while reducing the image quality - it becomes more pixilated. The better the image you start with, the more you can digitally zoom in without ill effects.
Also, know the limits of Thermal, it is great for detection, not identification. If you need to be sure it is a raccoon and not a house cat, that is another thing.