I looked at more expensive dethatchers, but finally bought a Brinly. This brand sells in 2 versions: the very light 40" unit sold by the big box home centers and a heavier 48" model sold by power equipment companies. I have the latter. I tow mine behind my zero turn mower. 2 passes at 45 degrees to one another. It works flawlessly. I don't find any need for weight in the tray. Deere sells what looks like the same unit, but with retractable wheels. Very nice, but I didn't want to pay the extra money for something I only use once a year. These light units can be surprisingly aggressive depending on how low you set the tines.
I bought mine from Chappell Tractor in Milford, NH.