When testing the effectiveness of these hoods I think the test needs to be done both with the Jeep parked with the engine running, and with the Jeep at highway speeds. The AEV hood in particular takes advantage of the low pressure area that is created just behind the leading edge of the hood when the vehicle is at highway speed. The vents are positioned right below this low pressure area, so air flows up and out of the vents when the vehicle is at highway speed, which draws more air through the radiator. Putting a thermometer under the hood with the vehicle parked and the engine running may not show a difference, but testing with the vehicle at highway speed should show a difference.

The AEV hood does let water into the engine compartment though. Not much, just enough for the fan to blow it all over the place.

That TOTL hood looks really good. The vents are bigger, and I'll bet it does a better job of cooling at low speeds, such as on 4x4 trails. If I had seen it before buying my AEV hood I think I would have bought that one instead.