I have had good service out of many different brands of dogs. The TSO dogs that came with they MTR triangle fit my bench as well as any others have. I also have the Festool ones from one of the MFT sets, they are the ones with flats machined into them. I don't really get the point of the flats? Maybe they are intended to have greater contact, to keep from denting softer materials?
I use the Parf Dogs for my track saw cutting station, 2 different lengths for differences in material thinness. I even have a cheap Chinese set from Amazon, and they fit well too.
Part of it may be that my table is drilled with the Parf Guide System. They are very precise.