Given the problems with the EX723 series' 3D pictures, it's a huge relief to find that the KDL-40HX723's 3D abilities are in a whole different class.
The main reason for this is that they suffer far less from the dreaded crosstalk double ghosting noise. In fact, with bright scenes there's practically none of it; the Wimbledon finalists during the BBC's 3D Wimbledon footage looked crisp and ghost-free while the cables of the Golden Gate Bridge in Monsters Vs Aliens were free of echoes.
The situation isn't so impressive during dark scenes. The current classic scene for revealing dark crosstalk is the lantern sequence in Tangled, and there was some evidence of ghosting around some of the lamps and around the spires of the distant castle.
However, no TV has so far been able to show this scene without any crosstalk at all and the amount generated by the KDL-40HX723 is low compared to many of its rivals.
Not having to squint through reams of ghosting noise makes it easier to appreciate the other strengths of the KDL-40HX723's 3D picture quality. For instance, it's easy to see the benefits of Blu-ray's full HD 3D system, even on a screen as relatively small (by 3D standards) as this.
Also, while Sony's bulky but acceptably comfortable 3D glasses do take quite a lot of the brightness out of images, the set's edge LED lighting delivers enough punch and vibrancy to counter this. Colours are more natural and dynamic than they tend to be with 3D footage.
Motion occasionally looks a touch juddery during 3D viewing for some hard to fathom reason, but for the most part the KDL-40HX723's 3D pictures are very accomplished.
The KDL-40HX723 is also a useful 2D performer. Fine detail, propelled by the impressive brightness, is terrific and clarity takes only a minor hit when there's a lot of motion to handle, though you do need to engage the motion processing to get the best from the set.
Colours with HD and standard-def footage alike are vibrant and natural after a little tweaking (the main presets leave skin tones looking rather ripe and the overall tone a touch warm), and blends are immaculate, even without calling on the Smooth Gradation processing.
The KDL-40HX723 also makes a better job of upscaling standard-definition material, particularly low quality stuff from the web, than any set we've seen, presumably thanks to X-Reality Pro, which was expressly designed to get the most from online video.
Black level response is usually a tricky area for edge LED technology, but the KDL-40HX723 handles it very well for the most part. Blacks are impressively dark, so long as you don't leave the backlight setting too high and that profundity doesn't come at the expense of too much shadow detail.
One final positive about the KDL-40HX723's picture performance finds the set running with an input lag of between 39-41ms when using its game mode. This could be better, but it's unlikely that such a figure would lead to any significant detriment to your performance when playing console or PC games.
The main flaw in the KDL-40HX723's picture is that the backlight can look a bit uneven – particularly in the bottom corners – if you don't calm it down considerably from its preset level. Patches of extra brightness can also occasionally be seen when watching 3D, thanks to the extreme brightness the screen defaults to in 3D mode. The good news is that you can iron out the vast majority of these inconsistency issues without over-compromising dynamism.
Another issue is that the KDL-40HX723 does demand considerable effort to consistently get the best from its picture potential, thanks to the numerous processing options available. It's tempting just to turn every bit of processing off, but if you do it quickly becomes apparent that some of the tools - motion compensation, advanced contrast and some elements of the noise reduction in particular - can really improve the way pictures look.
Given that tolerances to video processing differ from person to person, the only thing anyone who buys a KDL-40HX723 can do is go through everything one step at a time to see how they feel about what each processing element does.
One last negative concerns the KDL-40HX723's effective viewing angle, as the backlight inconsistencies increase and the overall contrast range decreases pretty rapidly once you start watching from angles beyond 35° or so.