I have not ever owned the aquarium products, but I did used to consult for hydroponic agriculture. In our shop, the pH and TDS meters were always the go to for suggested units. Especially because of the customer service we would receive if any issues happened to the device.
I purchased Hanna testers with a grant for river testing. Our hach brand test equipment worked but for field students the equipment was too heavy. Hanna worked just as well and the students could fit them in pockets. I would love to own some for my tank testing!