"Increased Colour Gamut+Studio Reference = PZ800TXH KILLER"4.5 starson by Megaloma
Pros: Jaw dropping picture in Studio Reference mode, all the picture tweaks you'd ever use, deep, rich sound for flat panel speakers, viera cast a nice, currently gimmicky bonus.
Cons: $500 premium a little high for essentially increased colour gamut and viera cast that is of little value at this time.
Summary: I was so shocked by cnet's rating of the Panasonic TH50PZ850U, that I had to write my first cnet review after spending a with each tv. I purchsed the TH50PZ800U THX model of this plasma at a summer sale for a $500 discount. The tv had hands down the best looking image compared to all the tv's in store such as the sony xbr4 and the samsung toc. I was seriously considering the xbr4 since fall of 07 to replace my samsung 1080i capable crt. After purchasing a PS3 a couple months later, I was set on finding a tv that addressed the issues that kept me clinging to my crt: black blacks levels, high contrast ratio, colour accuracy, long panel life with no burn issues.
The xbr4 impressed me with its colour accuracy, deep blacks (for an lcd) and improved speed via 120hz processing. I knew the THX panasonic plasma was coming and would have deeper blacks, naturally faster speed and I was waiting to see how the colours would compare. I was glad I waited for the thx enabled panasonic. It completely trumped the image of xbr4 and the price discount had me sold. I enjoyed the tv for a week with an assortment of bluray movies, games, dvds and my imac through a dvi to hdmi adapter. Everything looked amazing in thx mode with a few minor modifications. If you own an intel imac, I strongly recommend a dvi to hdmi adapter and the mac dvi adapter. For about $50 of cable, you'll get a picture so clear and vivid, that it switched me to a wireless keyboard setup to do virtually all my computing through the tv. You'll save some dollars compared to apple tv and won't be limited by apple tv interface.
After a week with the pz800, the salesman from the store told me the 850's were in at that I should have a look. Both tv's were setup side by side with thx set to my modified preferences on the 800 and the studio reference mode on the pz850. The panels were running planet earth's pole to pole disc and the 850's increased colour gamut was apparent through the subtle colour details that could not be seen in the 800. The arctic ice colours have finer green and blue details (the snow and ice just have extra sparkle), additional colour range can be seen in the feathers of the birds of paradise (greater black detail also) and the rich red hues of the seasonal forrest transitions shots are absolutely breathtaking on the 850. The THX panel in direct comparison looked muted to me. I paid the sales price difference and left with the new tv.
After a week with the 850, I have no regrets about the $500 upgrade cost. The extra 'pop' in the colours is worth the price even if the colour accuracy may not be a 100% accurate in testing, they are far more appealing. I can see what cnet was going for in their custom setting for the 850 as it appears more like the thx mode of 800, though very comparable to the studio reference (you can't exactly duplicate thx mode on the 850 through the pro settings). Basically, between the studio ref and pro settings, you have the choice between the thx modes extreme accuracy and the high colour pop of the studio reference. Would have been nice if panasonic include the thx mode in the 850 though. Overall the difference between the two for movie like sunshine on bluray is that both will treat you to an amazing, colour accurate image, but on the 850 you will 'feel' it.
If price point is not a major issue for you, I recommend the 850 over 800 hands down. After a week with each tv, I feel comfortable that the 850 with its higher colour gamut will still keep me satisfied when the xbr8 and the kuro/panasonic plasma come out over the next year. Maybe in a another the year, the fun but pointless viera cast will have some uses that are not apparent now. Panasonic, please at least offer more customizable weather (major US cities only), stock info (more customization of the main view and more currency/commodity price tracking options would be nice), and choice of major news sources.
If you have the chance, compare the thx to the studio reference in store with some high def media you are familiar with (the difference is even noticeable in the Vivid setting most stores use). I did and I feel more confident that the 850's image production will age better as media is produced that actually takes direct advantage of the higher colour gamut. Extreme colour accuracy be damed, treat your self to the most breathtaking image you've ever seen in a consumer television.