I did this 3 months ago - cancelled Verizon DSL and went to Comcast. Verizon seemed to be throttling my speeds which had been stable at 6Mbps and had no interest in fixing the issue.
The install was very professional and I am now getting 20Mbps down and 2 MBPs up and saving money vs my old ~4.5Mbps DSL/phone service.
I am using Ooma for phone and fax and it works great at ~$5 a month - you could also look at Google voice / OBI100 for phone.
I must admit I was concerned about swiching to Comcast - but it has been great so far. My son also switched to Comcast around the same time it is working great for him as well