(ported comments from OSRGaming forums thread
I'm gonna chime in here with my personal take on things. This was also what I held to before getting exposure IRL to military grade Low-Light, Thermal, and IR Nightvision devices.
There are several varieties of ewhat you are talking about when you discuss Infravision, Ultravision, Low Light Vision, and Darkvision. Each of which has been described in-game as representing a variety of mechanisms.
Thermal Vision is the classic "Predator vision" most often ascribed to Infravision. Colored blobs of varied heat intensities. Thing is, this has been refined into several specific technologies that offer widely differing resolution and subject detail. Modern military equipment still cannot let you read (unless spelled out in thermal ink/tape) but it is incredibly detailed otherwise. It is currently the tech used to allow vehicles to operate in blackout dust storms. Modern sensors can reach thousands of yards and still retain detail resolution and features of the subjects under observation. Instead of the older low-res spectrum color scheme, they are now black and white and can be seen commercially in games like CoD MW2 or Black Ops with the C130Gunship scenarios and such. They can detail ground features, trees, buildings, people, bodies, vehicles and more, so even undead can be detected in anything but the most extremely homogenous temperature-stable environment. They are also perfectly functional in broad daylight. There is ALWAYS some level of thermal variance that lends itself to sensor exploitation to produce more or less detailed fields of view. This nowadays is represented in game by Darkvision instead of the classic Infravision.
Ultravision purports to be based on the UV spectrum as opposed ot the IR, but for all intents and purposes can be observed equally from either side in basically the same way with each versions specialized sensors. Modern military IR nightvision is the "Green" vision everyone is familliar with from Silence of the Lambs, Pretty much any NVG equipped FPS Shooter game from Delta Force up to the CoD MW3, and cheap-ass celebrity sex tapes. These create a fully detailed visual field by taking advantage of the ambient IR signature (far more sensitive than simple Thermal vision) reflections, allowing you to see the reflected IR just like the visible light spectrum you see is the reflected light from objects. The "starlight" scope working to combine light amplification with IR collection represents this kind of thing and covers monochrome Low-Light, Infra or Ultravision. This can be augmented either by tech or by nature with IR or UV emitters, producing an illumination source of the spectrum being observed that can then afford reflections for the sensor to resolve. This DEFINITELY will pick out undead, and can even allow you to read print. This is why in fiction focusing on the Drow (120 ft infravision) they screen their eyes when being stealthy because they are organic IR emitters, exactly like the IR spotlight in my NVGs or weapon sights. This differs from more passive IR mark-1 eyeballs possessed by Elves and Dwarves with only 90ft or 60ft. Insects are primary responders to UV spectrum emitters, which is why they bait into the bugzapper so easy, and Underdark predators of the insect variety can be expected to be the same.
Light enhancement low light vision is more like the software filters many are familiar with in theor phones and cameras. These allow full-color vision in limited visibility areas and is represented in modern games with Low-Light vision traits. These are the ones that represent the excellent night vision of species like cats.
On uses and abuses, I have my Infraviswion/Darkvison enabled characters operate outside the circle of illumination of bright light sources (Torches/lanters) but can often operate fully within the range of magical weapon illumination or things like Faerie Fire. Your "Light trap" proposition is ALREADY REFLECTED in the game with things like the Flare spell! There are also aready rules for dazzling/stunning effects of surprise light exposure to infravision equipped characters, but it WOULD NOT BE WORSE than that of say.....Drow. A much more limited penalty effect than that of the BtB Drow for regular Infravision useage and interdiction, if any. Usually it takes a round of temporary blindness to reset from Infravision to normal vision when it applies. (why even my Infravision enabled characters often invest in Blind-Fighting proficiency).
On the Gauntlets, several of my varied characters have sought them out. They are as mentioned a mainstay utility magic item. They are also a surprising addon for NON-Fighters. We had a Mage in our party that got tired of listening to the Thief and the Fighter argue over who/how to open the door and simply stepped up and BBLG/ripped the door off the hinges, chucked it aside and stormed into the room in disgust.
Yes, 25 Titan Strength. In the STATS. (24 is Storm Giant, and ancient huge red dragon)
(more comments in original thread)