I opted for the Hitron CODA Modem-- a DOCSIS 3.1 model that's one of the cheapest Xfinity-compatible models I could find for $100. It supports download speeds up to only 867Mbps, but that's still ...
(Savings are shown for Xfinity and vary by cable service provider. No cable modem is compatible with fiber optic, DSL, or satellite services from Verizon, AT&T, CenturyLink, Frontier, and others.
Modems and routers can experience hardware and software glitches, even if a reputable company like Comcast services them.