Both will be a very good choice, and you should be happy with either.
But its really going to come down to what suits you & the enviroment it will be in.
Which is better is really more about personal preference than anything. Some like the brighter image a LED produces, some prefer the more natural image of Plasma.
Few things to consider:
1.
Room Size & Vieweing Distance
You need to determine what size you need or want.
IF its under 46" theres no point even thinking Plasma. Go with a LCD/LED TV.
Over 50" then considering a Plasma is worthwhile.
2)
Lighting Conditions
If the room you are in is very bright, with lots of sunlight, and this is when you watch TV the most, a LCD/LED might be your best best.
They are Brighter and tend to perform better in very bright enviroment.
If the room has controlled lighting, curtains you can pull, then Plasma will be a good option.
Plasma TVs also tend to reflect light more than a LCD/LED.
If for example, if theres a Window that light can shine through onto the TV, LCD/LED will hide the glare more.
This is because of how they are constructed. LCD/LEDs use a anti-glare Plexi-Glass type screen.
Plasma have a glass screen.
Thats not to say you can not view a Plasma in bright room. Im only saying that LCD/LED tend to be brighter, and do better in such an enviroment, especially if bright light hits them.
3)
Color Accuracy
Plasma offer deeper blacks, & more natural richer colors. The image accuracy of a plasma is much better than any LCD/LED can produce.
So when it comes to image quality & accuracy, Plasma wins.
But .. See point 2
Plasma tend to have a more natural, cinematic, tone to them.
4.
Energy & Wieght
Either can be wall mounted. But Plasma TVs are heavier. So something to consider if you want to wall mount.
Plasma do use a little more energy than a LCD/LED, so if energy use is a major concern, and you want to go green, LED/LCD wins hands down.
Plasma will also generate slightly more heat.
They both have thier advantages and disadvantages.
But either should last you a very long time, and should be about the same lifespan.
As far as all the other Plasma "problems" .. many of these are simply myths, and untrue.
-They do not require frequent servicing.
-They do not have shorter lifespans. They are 100,000+ hrs to the half life, and can last just as long as any other TV.
-Image Burn In is not a problem.
-They do NOT burn out pixels.
Quote from article:
pixel failure is not only untrue but impossible. "A plasma television isn't like your laptop computer or any other liquid crystal display, in which pixels can fail,"
Link to article:
USATODAY.com - Debunking myths about plasma television burnout
This guy lays out the differences pretty well. Might be worth a look.
Plasma or LCD? - YouTube LCD vs Plasma
Plasma "myths" Debunked - YouTube Plasma Myths Debunked
So in short, the 3 main things to consider are:
1) Screen Size 2) Enviroment 3) Which technology looks the best to you personally
The rest is simply myth.