I finally got rid of Comcast/Xfinity for TV. They kept raising prices and cutting content. Went to the Xfinity Store (don't even try the phone) and they couldn't do anything for me. I'm sick of shopping promotions and getting stuck with one to two year contracts anyway. They truly suck in every possible way.
I went with Hulu Plus Live TV which includes more live channels, Disney+ and ESPN+. Soooo much more content than what I was getting for a higher price from Xfinity. No contracts, so I can switch to a different streaming service anytime, if needed.
I kept Xfinity internet (for now) but saw no need to keep the 1200 Mbps (1.2 gig) speed tier they had slowly raised me up to over the years (and charge more for). All the ISPs lie about what the average home needs for internet speed, suggesting that at least 500 Mbps or even more is needed for 4K streaming. I read that 150 Mbps was more than enough to run four simultaneous 4K streams and more bandwidth is only needed if downloading massive files from the internet.
So, when I dumped Xfinity TV I also reduced my internet speed to 300 Mbps, a $30/month savings for me. I've been at 300 Mbps speed for several months now and have not noticed any issues streaming Hulu Plus Live TV and/or Netflix at the same time on several TVs. No noticeable difference in internet speeds on computer connections either.
Here are Xfinity Internet prices for my area. I had to add the actual speeds of the different "named" tiers to the screen shot because, of course, that info isn't included anywhere on the same web page. You just have to rely on their deceptive descriptions of the capabilities of the different speed tiers, which are included on that web page.
These are out-of-date prices now, since Xfinity just raised their already high prices for internet by $3/month. They also reduced the discount for autopay/paperless billing from $5/month to $2/month. So, my bill went up $6/month. I had already been thinking of trying the 150 Mbps speed and this prompted me to do it. The price is $71/month ($73 - $2 discount for autopay/paperless). I've been using it for a week now and have seen no lags or interruptions in internet or streaming connectivity. My experience so far is indistinguishable from the 1200 Mbps speed I had originally that cost $52 more per month.
Brightspeed Internet installed fiber in my neighborhood last year, so now that is available. Prices are competitive or a little better and they provide a free modem (ONT) and free installation. When I was shopping at the Brightspeed web site, I noticed that their descriptions of what is doable with the different speed tiers suggest that the 500-1000 Mbps speeds are needed for 4K streaming.
A chat window came up on the page, so I asked why it says 500 Mbps or gig is needed for 4K streaming and wouldn’t 200 Mbps (the lowest they offer) work just fine for multiple 4K streams? This was the answer: "The 4k streams worked for both plans but the difference is the 200Mbps only cater 4-8 4k streams simultaneously while the 1G work with 20+ 4K streams simultaneously.” LOL, as soon as I get 20+ TVs running 4K streams simultaneously I'll think about upgrading.