Pn43d450 or 42pa4500

I'm very happy with my PN43E450 and I payed $480.
At $400 it's steal!
I never babyied mine, had the cell on 20 and Constrast at 95 to 100.
Just left it on for 10 days straight so those phosphors could cook away.
Watched Dish HD most of the time and some dvds and and Used the movie
fit mode 1 and 2 to fill the screen.
Overnight I left it on the Tru or ID channel as they have large but
opaque logos and no black bar programing.

Yikes 100% contrast You did turn it down after you "broke" it in right???
Samsungs have had far better contrast than Lg in the past due to their capability to show darker blacks.
Samsung is also doing better this year than ever before in regards to image retention or burn in an area which Lg hasn't done well in the past.

yes everyday in the evening, 100% contrast in the day time.
The break in takes more than 100 hours.
That's a VERY conservative number, IMO.
The heat was very high the first 5 days and on day 6 I noticed a slight
drop and it's been subsiding since then and the picture has improved.
I'll tell ya for the first 5 days it's like cooking a phosphor stew.
A very interesting and warm electronic phenomenon.

I thought people ran them at lower contrast settings for the break in to avoid overheAting and burn in. I know people are saying the new Plasmas can be broken in at higher contrast but I'd probably still play it safe.

They generate heat, it's natural and how they operate.
If you really want to lower the power/heat lower the cell
from 20 to the Energy Star default of 6.
At cell 6 it's getting less than 1/3 power/brightness
that results in a washed out looking picture.
With this years Samsungs you don't have to baby it just
avoid solid logos for long periods (very few around anyway) and black bars.
With the Panasonics probably yes baby it.

http://reviews.cnet.com/8301-33199_7-57449881-221/samsung-plasma-wins-cnets-accidental-burn-in-test/

Might look washed out in a bright room. I'd probably never feel the need to bump contrast past 40 in my viewing area. That test should be taken with a grain of salt though as the panels were both in their respective cinema modes not calibrated to the same light output and the Panasonics have brighter panels than the Samsungs this year. You shouldn't have to sacrfice on any modern plasma but most people don't buy a plasma for it's brightness.

I wouldnt worry to much about it just because Samsung is doing well with image retention doesn't mean lg Plasmas will catch fire and spew molten burn in the minute you turn it on. I am only speculating on which plasma is better based on how Plasmas from each company have performed in the past the only way to know for sure would be to try each and if you don't like one, return it.