Only advantage is combined billing
Only advantage is combined billing, which means one less check to write (if you pay your bills the old fashioned way through the US Mail). Like many people my age, I pay my bills online through the provider's website using my debit card. Pretty much the only check I write is to the landlord for the rent on my half of the duplex I live in (since the landlord does not have a website nor does she take debit cards).
On the other hand, they might offer some sweet deals with quadruple play (cellular/landline/data/video bundles). A few years back, Comcast did not offer bundles and you had to buy the services separately (and at full price). With the Great Depression 2.0 (what I call the recent recessions), the MSOs had to offer some sweat deals as the cable and internet are the first cancelled when the breadwinner of the family gets laid off from his job.
I remember when I first got broadband (high-speed) internet, I got two separate bills; one for cable and one for HSI (this was in 2002, when I was living in Iowa, which is Mediacom turf). And that was back in the days of @Home and the discount for using a purchased modem was generous.
All of my CPE (including my EMTA) is customer owned. The only Comcast owned equipment in my house is the CableCards in the two TiVO boxes I own.