I would probably rank temp guns as follows:
3. Odonnel or whatever they have morphed to
I have a Raytek that I bought in 2000 which is still going strong and is still very accurate. I check it against my buddies Exergens, OFNAs, Odonnels, etc and it is within 2 to 3 degrees of most of them. Be careful of the ones from Radioshack, Harbor Freight, or some other outlets. They may not be too accurate and may cause you to burn up a motor/ESC/nitro engine.
It's not what you know; it's what you can prove.
The only thing that is for sure is that nothing is for sure!!!
The needs of the many outweigh the needs of the few, or the one.
There are 2 things in life that are infinite: the universe and stupidity.