I have optimum 60mb download and 30mb upload and I can run a bunch of phones and computers and be watching youtube and my parents watching netflix all at the same time with no lag.
You shouldn't get the best one but you shouldn't get the worst one either. I would say that depending on the amount of devices you have around 1-2mb/s per device is good
I have optimum and my router gives out two wifi networks. My home network and the network that says optimum wifi for everyone to use. So I would probably use that network.