It's all preference. It's generally a given that you have to spend more on an LED to achieve the same performance as a cheaper plasma. Room characteristics may also eliminate plasma as an option since even the best plasmas tend to wash out and lose contrast under bright lights. LED/LCD based sets have less of an advantage now since most of them are either glossy or some type of glass finish so they tend to be reflective.
Brightness is also a huge deal among people who buy LEDs, but as someone who owns both I really don't understand this argument as even my plasma can be way too bright if I wanted it to be. An overly bright picture is just not natural and not necessary.
My favorite thing about plasma, and its biggest advantage to me, is how well it handles motion. Even while the best LEDs (Sharp Elite, Sony 929) handle motion excellently, they still don't look as natural or convincing as a plasma.
ht Panasonic 60" ZT60, Monitor Audio: Silver RX6, RX Centre, RX1; Martinlogan Dynamo 700, Marantz SR5006, PS3, Oppo BDP-103D, Panamax M-5100PM
2ch Sony 32" W650A, Sonus faber Toy Monitor, REL T3, Marantz PM8004, Sony BDP-S1000ES, JVC T-X3 tuner, Apple TV, Peachtree Audio DAC•iT, Panamax MR4300
pc Monitor Audio Radius 90HD, Audioengine D1, FiiO A1
+ Sony 65" XBRX850B, Sony BDP-S5100