Overall Impressions
In developing the TC-55CX400 Panasonic focused on offering good picture quality to a price-focused customer, and did a pretty good job. Colors compare favorably with some step-up competitive models costing hundreds more, although the set doesn’t provide all of the tools you’d expect to adjust the picture to particular lighting conditions in every viewing application.
Panasonic pre-adjusted the calibration pre-sets to accommodate typical living rooms (in standard mode) or dark viewing rooms (in cinema mode), trusting that people looking for an expensive TV aren’t going to care too much about getting the calibration adjustments just right.
Over all, the lack of important calibration settings, problems with video processing and motion compensation, and some mottled uniformity make it tough for this set to compete with most step-up “mid-fi” 4K UHD models. Also, the $899 selling price at some participating retailers is a little high compared with some other competitive models in this class — like the 120Hz 4K UHD Hisense 55H7B costing $200 less and providing 4 HDMI inputs. That model also consumes an estimated $21 per year in electricity according to its Energy Guide sticker, and that’s almost half as much as the TC-55CX400.
http://hdguru.com/review-panasonic-goes-for-value-with-bright-tc-55cx400-entry-4k-uhd-led-tv/