Im my experience the single best thing you can do is use a new eero as your hub and then as a practical matter the mix and arrangement of other eeros makes only a trivial, though measurable, difference. The newer eero just handles that one heavy-duty task better than the old ones. It sends out a more powerful wifi signal and channels everything throughout the house better. My dad bought me a three-pack of the original eeros some number of years ago as a birthday gift at the pre-order price before they were in production and over a year later they arrived. : ) So I could use another brand but I am sentimentally attached to them and well, heck, they work. At a Christmas sale last year I bought a pack of two new gen eeros and a beacon at Best Buy. So I have mixed set of six set up in a house. Honestly, if I place one original eero really carefully in a place that causes ethernet cabling chaos, it will take care of the actual needs of my whole house, HD streaming, my wife three teenagers included with 30-plus devices active a lot of the time. But that's no fun. : )  Which, parenthetically takes me to another point-as a practical matter many people really would need just one eero, but I don't think the eero people are too keen on emphasizing that. Anyway, I worked with eero customer support for a while and arranged the six I had in the best possible fashion based on feedback from their looking in on my network and for me the performance between optimal and random throughout the house was not meaningful for real-world use. It was just chasing download speed numbers that were way more than anything needs anyway. I was most obsessed with my back porch on the total opposite corner of my house and a spot in one bedroom in another corner where no one every actually goes. So now I just have them wherever they will go most easily. I will say that even the new eeros definitely lose bandwidth in hopping at high speeds more than some other multi-pack router "mesh" brands. But I think the eeros are more reliable and smarter and more secure (unless you are worried about eero techs looking in your network) and are much better supported over the long term. But to clarify my main point, you could use an original eero as the hub and if you goof around enough maybe you could even use a single original eero as your only router but if you are looking for optimal performance in my experience and after my experimentation the single best thing you can do is to use a second-gen eero as your hub. After that I would guess you can mix and match without much difference. That's a guess based on the results of my own obsessive two-week-long numbers-chasing quest.