Those models are modem only, the zoom is cheaper then the motorola.
You dont want to buy an all in one device because is is just a crappy router mixed with a crappy modem and sold at a premium, then when the crap dies you have to replace both.
How big of a home do you have, how many devices, and do you want dual band (dual band means it can use the 2.4ghz band and the 5 ghz band to provide more bandwidth assuming you have devices that support dual band).
Also what is your total budget?