Great questions and you are not alone in this dilemma. I'll try my best to help.
For most guys, it simply comes down to your budget. Don't get me wrong, I'm not saying it's a matter of whether you are rich or broke, I'm saying it often just depends on how much money you want to spend. Some guys (even with the money) could never dream of spending $2k on a night vision scope and they are perfectly happy with the digital NV like the Photons. However, there is some truth to the saying, "once you go thermal, you never go back."
The Photons are excellent, a real bargain for the money. With a good external IR light you can pretty easily see hogs out to 200-225 yards. I used a Photon since the day the first ones were released and I've killed a lot of hogs with them, especially the XT models. They work great but the thing about digital NV is, when it comes to seeing animals out past 225+ yards, you never know what you are missing because.....you never see it. I hope that makes a little sense. Basically you don't know you are missing seeing hogs out there at 300-400 yards because you never knew they were there. With thermal, you see them and go to them. That's how you kill so many more hogs with thermal. You see hogs you'd have missed otherwise.
The furthest I can see in one direction in my pasture is 450 yards. I can stand on my back porch with thermal and scan that whole field in 5 seconds and tell you affirmatively there are NO hogs out there. With something like the Photon, in 10 seconds I can tell you there is a 95% chance there are no hogs within 200 yards of my back porch. That's a big difference. I'm missing seeing many acres of land.
A lot of it also comes down to how you are going to hunt. If you are going to sit in a stand with a feeder at 50 yards and you won't be able to see past 200 yards in any direction, digital NV will work fine. It's still more work than thermal scanning around and you will still miss seeing a few hogs from time to time but generally speaking, you won't miss seeing a ton of stuff.
Thermal also has uses while deer hunting during the daylight when using it as a spotting scope because again, nothing can sneak past you. Thermal is also one of the greatest tools you can have on tracking job because you can find a dead deer or hog laid up that you'd have walked past and never seen without it.
I want to mention a couple other things....
Option 1. Sightmark Photon, 650 bucks
Which Photon is this? The new RT's that aren't released yet? I ask because there has been a price drop and the most expensive Photon XT is the 6.5x50L and it's $599 now.
Option 2. ATN Thor for 2000.
Don't take this the wrong way and I don't want to be rude about it, but I would not suggest buying the $2,000 Thor. There are other thermals in that approx price range that will waaay out perform that Thor unit. I think most on this forum will agree.
I know I've rambled a good bit but if you'd like to talk on the phone one day, give me a call. I'd be glad to help answer any questions I can. I spend most of my day talking to people in the exact same scenario as you are, I'm glad to help.
- Jason