There's nothing wrong with using the cigaratte lighter socket to power a radio as long as you understand the limitations.
First is current capacity. Lighter circuits in most modern cars are good for 10-15 amps. Typically, 50-watt 2m ham rigs draw around 10-15 amps on high power. However, most of these radios have selectable power outputs. Drop the power down to 10 watts and the current draw is much less--well within the capabilities of a lighter socket. In a metro area, you can probably hit most 2m repeaters at that power level. You just have to keep in mind that out in a rural area, you may need to run high power, but the lighter socket may not take it.
The real problem with this set up is resistance, voltage drop, and heat. Lighter plugs usually don't make very good contact in lighter sockets, so the connection has a high resistance. A low currents, that resistance isn't much of a problem. At higher currents, that resistance translates into a significant voltage drop which means that if you try to run the radio at high power (high current draw), the voltage drop may be so high that the radio does strange things because of the reduced voltage. Also, a high currents, that resistance translates into heat build-up in the lighter plug which will melt the plug.
The second problem is noise from other devices in the vehicle. Because the lighter wiring often goes through various fuse and distribution panels under the dashboard or under the hood, the lighter wiring often picks up electrical noise from the alternator, ignition system, fuel pump, or various on-board computers. My experience is that most problems with electrical noise can be traced to poor power wiring going to the radio. Running heavy gauge wires directly to the battery often cures the noise.
Can you get by powering a radio from a lighter socket? Yes. Is it the best way of doing it? No.
