I guess it's a good thing you are not too proud to ask, but I find it interesting that you are in the business of selling AR parts and accessories, and you look for this kind of information here.
I would think that someone in the AR business would have the answers to this type of question.
He could have given the customer a ******** answer based on the manufacturers claims, but instead he came to people that have experience with the dozens of devices available and asked for their opinions. Now he'll be able to suggest a device that the customer will be happy with and not just the one with the highest profit margin.