A variety of high end freon detectors are available from several manufacturers - CPS, Leybold Inficon, Robinair, TIF, and Yokogawa.

Any specific model/manufacturer significantly better than the rest in real world performance?

Use the dye. It is more accurate and cheaper than any instrument.

Don't know the model but I hear Yokogawa makes the best. I have had many Robinair and TIF and we only use them for quality control of repairs where the dye hasn't had time to be of use.

The problem with all sniffers is that you can only get close with the detection. With the dye one gets a visual image of the problem. This often can determine the type of repair with great benefit.

I have learned that no type of leak detection is absolutely foolproof. Dye is about the best thing going but, you are restricted to only where the UV light will go. Sniffers are pretty good too but, a good fart can set one off. Point being I don't rely soley just on one method of leak detection.