phone service (cell and other)

I have been wondering about different locations and cell phone service.  I have Sprint and have been fortunate that I've had good service everywhere.  But what about someplace that has poor or (heavens forbid!) NO cell service (I hear such places still exist)

I used to have Vonage for home phone service.  Does anyone use this?  I can see how it might be helpful if you have limited coverage.  As long as you have high speed internet access.

Any insights/advice/suggesions are appreciated.

We use Verizon and have had good coverage everywhere but the far corner of Washington state.  When we were there we actually had to purchase a cell phone signal booster.  (about $250)  Very expensive but we simply could not do without phones for 3 months.  It's very rare to have cell phone problems these days.

We have CellularSouth...which is a local company to the south but we have never had any trouble with service no matter where we go....countrywide....we have been from NC to WA to FL to south TX.....no problems. You can find them onlihne at cellularsouth.com. They have a 79.99 plan that is unlimited smart phone and you can add a line for 1/2 price. works great for us.