I recently had fun cancelling my Comcast internet after switching to fiber. When asked why, I said "4x the download speed and 20x the upload speed for half the price". The tech just said "can't argue with that..."
Yep, with all the horror stories around retentions and upselling I personally never had any issues in that front. I honestly tell the rep that I have a better deal on the technical level elsewhere (that their offering can’t match) and it was always easy.