I own a FLIR PS-24 and can tell a huge difference between that device and the FLIR Scout III 240. First, I'd like to state that the PS-24 is an excellent thermal device and if you get the opportunity to own one for a good price, pull the trigger on it because it will not disappoint. The difference between the PS-24 and the Scout III 240 in this case relies in HZ refresh rate in my opinion. The difference between 9HZ (PS-24) and 30HZ (Scout III 240) is like the difference between a high end video card on a gaming computer and a good laptop. By that, I mean you will get a bit of stutter in the device (laptop) vs fluid image viewing (gaming computer). Both will have a 'reset' effect (refreshing the screen image) with a audible 'clicking sound' that I've noticed, but the 30HZ Scout III 240 has a clearer and more fluid view. I also think the Scout III has brighter images and better resolution. I don't want to sell the PS-24 short. Both have White Hot and Black hot which work exactly the same as well as Insta Alert. The Scout III 240 also has something the the PS-24 does not have. Graded Fire. Graded Fire is supposed to improve on Insta Alert by enhancing it.