While it's easy to be impressed by the range of picture adjustment options, the results of even the most painstaking fine-tuning are rather disappointing.
The single biggest problem is the patchiness of the backlight, which finds some parts of the picture looking clearly lighter in tone than other parts. We spotted at least four areas of extra intensity, all quite large, and all clearly visible while watching any predominantly dark footage.
At its worst this luminance inconsistency is very distracting, thereby breaking the first rule of good TV pictures.
It doesn't help that these pools of extra brightness are sufficiently large to compromise the 37LE5900's general black level response, leaving dark scenes looking greyer and messier than is desirable.
The impressive black level efforts of recent edge LED sets from Sony and Philips throw the 37LE5900's shortcomings into stark relief.
Colours suffer slightly as a result of its contrast woes, lacking a little of the naturalism and subtlety noted with some other recent LG sets. They're still quite punchy and bold, though.
More bad news arrives by way of standard-def performance. A combination of what appears to be fairly low-rent scaling processing and some pretty obvious motion blur leaves even decent quality standard-def sources looking a bit soft and mushy.
Colours are noticeably less accurately toned with standard-def sources too, a once common flat TV problem, but one that now ought to be handled rather better.
The 37LE5900 isn't bad with HD, at least when the content on show is predominantly bright and colourful and so not prone to highlighting the backlight consistency woes. There's a reasonably crisp feeling to proceedings, with good detailing and a general dearth of noise. Even the motion blur noted with standard definition is much less troublesome with HD, especially with the TruMotion processing in play.
With this in mind, it's a pity that TruMotion can generate a few little processing side effects, but it's possible to turn the it off if you find these get too overwhelming.
Perhaps the only truly unequivocally positive thing about the 37LE5900's pictures is a high brightness output that does its best to hide the contrast concerns where it can by driving colours and bright scenes out with an almost desperate level of aggression.