Nextel's push to talk feature is fast and free on most plans. If you have friends this is great. Saves you money and time.
To answer the coverage issue: Every carrier has towers in different locations. No 2 carriers are created equal. Sprint might work for you because they have a tower near your house and that is were you use the phone. But Nextel might not work for you because they are 3 miles down the road and cant penetrate your house. I could live 4 miles from you and Nextel works like a charm and Sprint doesn't work in my bedroom where I need it to work. You should be the judge of the coverage.. Every carrier gives you a trial period. Even if it is only the minimum that the law says 3 days. Use those three days to travel were you are going to be using the phone. If you don't and get suckered into a 2 year contract your loss.... You stick one carrier and you will never be able to get a phone again (unless you pay $500 deposit). They share their deadbeat list. PS: If you travel a lot Nextel, Sprint, and T-mobile lack the non major city coverage that AT&T (TDMA) , Cingular (TMDA), and Verizon have. Those three have been it longer and allow roaming on other networks. AT&T and Cingular
GSM coverage is not as good as TDMA nation wide coverage.
I have been involved with wireless sales for 13 years now. I hear everyday how blah blah is the best carrier and they say blah blah blah is the worst... Then 15 mins later another customer comes in and says the complete opposite. If there was 1 clear choice we would only have 1 choice.