Had Tracfone. Not bad, but the minutes expire if you dont use them and you have to buy another card. If you constantly use the phone its ok, but if you dont plan on using it you'd have to spend the money for the minutes anyway, so you might as well buy a regular cell phone.
I use T Mobile now, for 39.99 a month I get 600 minutes per month, free nights and weekends, no roaming or long distance anywhere in the US, and discounted calls to other countries. The coverage outside metro areas is the sticking point with T Mobile.
For what you want Eskimo, I'd really recommend either Verizon or Nextel. The walkie talkie feature is a real bonus, and doesnt eat into your cell minutes. My contract with T Mobile has been up for some time, so I could leave whenever I want, and I've been keeping an eye on the competition. Nextel is likely where I'll go, since they have Nationwide walkie talkie up now.