The X320 is good and given what I know now, would be the other primary option I would consider to my FLIR PS32. They now have the newer version that has video-out and apparently a better display.
http://www.flir.com/uploadedFiles/Hunting-Outdoor/Resources/scoutII_sellSheet.pdf
I like the PS32 primarily because it does what I need in what I consider a more handy size. That is a personal preference. I am not a fan of the boxy shape of the X320, but it is a good scope for the job.
Aside from shape, the big differences I see are the refresh rate (9 hz for the PS32 and 30 hz for the X320) and batteries. The faster refresh rate is better, but not a huge issue for the purposes of spotting. The PS32 has an internal battery. I happen to like the feature because the 5 hour run time is enough for most of my hunts. The X320 lets you change out batteries.
Both are rugged and both will work fine. I believe the X320 is still a little bit more expensive.
Positive ID is a bit of an issue with ~320/336 resolution, small lenses, and 1x optical power. You learn to do a lot of interpolating of what you are seeing based on size, shape, and movement, plus the all important environmental factors. On a night with low humidity, I can tell the difference between a broadside deer and hog at 200 yards. It helps, a lot, if the deer raises its head from the ground. Hogs and deer (with heads down) can look a lot alike at distance and from about any angle with thermal. At 120 yards, I can tell the difference between a deer and hog coming at me out of the woods (the woods are at 120 from a stand I often use).
Smaller critters? At 100 yards, it can be difficult to tell the difference between a bobcat and a raccoon if you can't see the tail. If you don't know the distance (and distances are hard to judge through thermal), then a coyote standing still can look a lot like a deer as the tail often does not show up or show up well and their profiles are similar. Deer and coyotes move quite differently, however, and that is often a key feature.
When the humidity gets high, the images become less precise, and while you still may be able to see quite far, much of the detail gets lost. So the effective range of the scopes will drop.
Another problem with using these spotters can be in the telling of the difference between bedded cattle in foot tall grass and hogs standing in foot tall grass. While the profiles can look similar, again it is the movement that gives them away.
Note that the most salient benefit of thermal spotters at this level isn't identification so much as it is detecting that an animal is even out there.
I don't know what other units were on display at SHOT that would compete with these, but I would not want to go below 320 resolution and if you have the money, something with 2x optical resolution is a significant improvement, but such scopes usually come with a significant increase in price.