we did this 2 years ago- my little brother and his wife have been without land-lines for almost 5 years.
at first it was an adjustment---hey- i don't have to look for the answering machine any more- i don't have to deal with missed calls at home- my phone is with me.
long and short-
we do not miss our land line- we do not miss the bill- we do not miss the answering machine-
for us- it was a good move that made sense- we both needed to carry cel phones for work- and figured why pay for both- if we have to have these- well- lets have these- and get rid of the other-
we do get good reception- have never dealt with a dropped call or out of service issues- i know though that some people do not get good enough reception/signal in their homes for it to work for them-
we had had our cel's for 6 months and knew we had good service before taking that plunge.
out in the woods/hills where one of my brother's live they have cels- but get no service where they live--you can send them a text message which will go through then they have to (leave home) to return or make a call. so---before taking that step i recommend making sure a cel will in fact work as a primary phone...location matters