Whirring electronics 4 star .....

I would give the television. As far as I can see that, but all the positive features have been highlighted already in the other reviews.
a point I would like to have additions, leading to the star deduction.

1. quite loud hum of electronics

This humming is roughly equivalent to a lamp with a dimmer features (volume level but still slightly higher).
Research from the Internet has shown that this is not an isolated problem.
While plasma TVs have an increased operating noise, but this humming being excluded.
For a device in this price range (in spite of the immense size) one might expect a consumer-friendly solution here

Supplement: phoned Samsung hotline yesterday. Appointment with a contract mechanic was determined and the plasma will be repaired locally. Even with Samsung this noise is not an unknown issue, as the TV technician brings the related replacement parts.

I'll keep you when necessary (Comment contributions) up to date

Addendum March 2015: adaptation of four to one star, as already after less than 5 years, the panel is broken. Runtime TV in the week up to 4 hours. Totally unacceptable in this price range