Wow! Anything over -104dbm (numeric, higher number = lower power) is the limit of CDMA. Phone's aren't designed to operate in such lower power environment... this is picowatts we're talking about.

As for coverage in general, no wireless company can provide perfect coverage everywhere (yet). VZW does have the best overall, IMO, but others may be able to server you better in that dead area. Luckily, they all have trial periods for just such situations.