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.
Bosch Master, ASE Master, L1
33 years MB technician