There are two models of the FLIR PS-32, both have the 320X256 microbolometer but the PS-32 has the 19mm germanium lens and the PS-32R has the 35mm lens. The both have InstaAlert and brightness adjustment and are the same except for the lens size, but the PS32R has a built in video output port for recording the image which the PS32 does not.
I normally recommend the standard PS-32 with the 19mm lens to most hunters because it has a wider FOV and excels for finding downed game in thick underbrush as well as being able to detect a fox, rabbit, coon, coyote, hog, deer, etc out 350 yards. At night, WFOV is your friend.
The PS32R with 35mm lens has a longer range of detection out about 600+yards, but the FOV is 1/2 the standard PS32. The larger lens with the same microbolometer increases the detection range about 2X but also makes it more difficult to find downed game at night due to the smaller FOV.
They are both ergonomic and easy to use and the internal battery lasts an entire night of hunting.
I have both of these and use them all the time, my PS32 is 3 years old and is my standard Go-To, if I forget to bring it out with me on a night hunt everyone is extremely mad that I left it at home....you will see 10,000X more game animals than you ever saw with any night vision device, it is a total game changer for night hunters.
Takes awhile of practice (couple of months of use) to learn how to judge size and distance but once you have enough experience not a problem, using it around the farm at ranges that you know is the best way to prepare for going somewhere you are unfamiliar with at night.
A FLIR RS32-35 or RS32-19 also makes a great thermal weapon scope for night hunting with similar range as previously mentioned above:
Here is a video I made through the FLIR PS32R-35mm:
Deer are 50 yards out and otherside of pond is 250-350 yards away in the video.