It is my understanding (and I gleaned all this because I live in VERY rural Michigan -- i.e. Amish neighbors! -- and we've gone thru phone and highspeed internet hell for years) that one company owns and services the physical phone lines, but other companies pay them to offer their own local and long distance service.  in otherwords, the physical lines (probably) belong to Verizon (or even AT&T) but other companies lease from them.  Fixes on physical lines will be no more or less quick regardless of who (whom?) you're going thru.  (Again, this is from experience.)  In our case, Frontier is the physical owner of my phone lines and they will NOT lease out to anyone.

We have two physical landlines (one for our second phone line and one for our fax server) and one line thru Vonage.  Going with Vonage on our main line allowed us to keep our old phone number when we moved 3 years ago.  I cannot give a 100% approval of Vonage but my IT guy tells me the problem is with the DSL connection, not Vonage itself.  Since it looks like you have cable modem, you shouldn't have any issues.  Vonage also makes it very easy to forward calls -- we can even port our phone number across country if we need to.  Heck, I could be working from TAHITI and you'd never know it!  (I wish.....)  You can also have your Vonage line roll over to another line (vonage or land) when the first line rings busy.

Alix