Have you done a search for owners threads and reviews?
Here's a review of the HX803 Sony HX803 (KDL-40HX803) 3D LCD TV Review - AVForums.com
Oh look, and here's one of the NX713 Sony NX713 (KDL-46NX713) 3D LED LCD TV Review - AVForums.com
Which did you prefer when you demo'd them?
Personally neither, as I have no interest in 3DI'd probably get a Panasonic 46G20 from Richer Sounds for under £700 with extended warranty (indeed I am quite tempted
)