I was told I could not disable their hotspot, nor could I set my own DNS servers. Since I kept having connectivity issues due to Comcast’s DNS being flaky, and not wanting to manually configire every client, I bought my own modem and wireless setup.
I've used my own DNS servers before. I have no problem making DNS queries to 8.8.8.8, and in fact I switched my PC to use it one time when Comcast DNS was down.
Overall, I’m rather happy with my current setup. I bought the most recent SB modem available at he time, got an Edgerouter and a Unifi AP. Took a few minutes longer to set up than a netgear or whatnot, but was able to use POE to put the AP in a far better location (it’s actually under my sofa instead of the closet where all my wiring goes) and have had a far more reliable and customizable experience.