Edge lit LED (99% of LED monitors) is a gimmick. There are small power savings and the monitors can be made thinner but they are no better in any other respect.
The thing you need to pay attention to is the quality of the matrix that is in-front of the backlight. This is more important when it comes to the quality of the monitor - and the only real way to do this is by reading proper reviews or seeing the monitors in the flesh.
xbitslabs do quality in-depth monitor reviews where they actually measure the response times, colour reproduction, artifacts generated by RTC, black quality, backlight bleed and so on. Unfortunately they seem to take quite a while to get reviews of new screens up though.