I've had Comcast / Xfinity for almost 10 years now.
Every now and then, I compare them to the other options, but they are always better value for money and offer faster internet speeds.
I negotiate a new deal with them every year or two. It can be a pain in the butt but I've learnt that one way to get what I want is to end service and then sign up again in either my name or my wife's maiden name.
A few years ago, I decided to cut the cord as much as possible. Right now we're paying $50 a month for internet in the 2nd year of a deal. The first year was $40 a month. Our speed is enough for simultaneous streaming and 4k streaming.
A while back, they introduced data usage limits. Our limit is 1000GB a month. We don't get anywhere near that. I think it was a good idea to introduce these limits because a very small proportion of people use a lot of the bandwidth.
We also have access to Xfinity hotspots. Part of the reason I use very little mobile data now is that I seem to be connecting to Xfinity hotspots in a lot of places and their speed is fast enough to let me do whatever I want.
One of the services Xfinity have introduced is Live TV streaming. I can access all my channels on any device in HD. We have the limited basic plus HBO / Streampix package. Some of the channels, including all of HBO, can be accessed outside of the home. We also have Netflix.
Recently, I took advantage of the Xfinity mobile promotion. I got a free phone worth somewhere between $100 to $200, and have unlimited talk and text and 100MB of data for free on the Verizon network.
There has not been any major outage with Xfinity in 10 years. I think that once or twice there was a period of a few hours where we lost service.
Overall, for the price paid, the speed and reliability have been excellent. The additional services that have come online in recent years - xfinity hotspots, live tv streaming and now xfinity mobile, have introduced more value with no additional cost.
I will add that the experience with xfinity mobile has been flawless too. While they piggybacked on Verizon, they have their own front end and processes and it works well. It's a high quality and efficient experience which are crucial to customer satisfaction. And, apart from taxes and data above 100mb, it is truly free.