I did some testing to evaluate motion blur on the LN-T4081. Here are the testing conditions.
HL2 Episode 1 running on WinXP
V-Sync enabled in HL2 Episode 1
LN-T4081 and Mitsubishi Diamond Pro 2070 cloned at 1920X1080 60Hz progressive from a EVGA GeForce 8800 Ultra
Picutres taken with a Cannon 30d set to FStop 125 and ISO 500
In the testing I rotated the mouse very fast in circles to produce the desired motion for testing.
First is a picture with no motion from HL2 Episode 1. This image serves a baseline for comparison.

The next two images are with LED Motion Plus set to on for the LN-T4081.


The next two images are with LED Motion Plus set to off for the LN-T4081.


Now for my comments on these pictures. Comparing the pictures it obvious there is motion blur on the LN-T4081. Most of the time there looks to be 1 primary image followed by a secondary ghost image. I picked the one pick where I could see more than one ghost out of all 20 or so pictures I took while testing.
Looking at the 2070 in all of the pictures you can clearly see the 60 Hz progression scanning that is taking place by the CRT.
In terms of comparing LED Motion Plus on/off I came to the following conclusion. The ghost images are noticable dimmer with LED motion plus on. This was the case in comparing all the pictures that I took.
To me it looks like we need to shorten the response time by half for 60Hz progressive refresh rate. My geuss is LED motion plus is not doing quite what it should be doing because the LCD pixel response time is still not fast enough. Based on the pictures I would say the average pixel response time is really over 22ms or so.
I am going to test and see if game mode effects motion blurring. My geuss there is likely no difference.