I would like to buy a new television. My first thought was to buy a plasma TV, but the room is very bright so I thought I might be better off with an LED-LCD set. That gave me the idea to jump up to one of the 4K sets. Unfortunately, there is very little 4K content to watch, and it will be a long time before we see it. What I did see in 4K TV advertising is the TV will upconvert the incoming signal. Have you seen any of the 4K sets upconvert, and if so, can you comment on the picture quality?If I was buying a new top-of-the-line TV, I'd almost certainly buy a 4K set, especially because Panasonic is not making its amazing plasma TVs anymore. Samsung and LG still make great plasma TVs, but you won't see plasma 4Ks because plasma technology is extremely inefficient at 4K resolution. If you are satisfied with a 720p or 1080p set, plasma is still an amazing value.You are wise to ask about how well the upconverting works. After all, unless it is a 4K signal, everything you watch is going to be upconverted.Watching 4K demo material in stores is truly breathtaking. But you won't get that kind of technical excellence at home, and as I have said, we are not done exploiting the full quality of our 1080p sets.A lot of 4K TVs look impressive with 4K demo material, but when you feed it a signal from a television broadcast or a Blu-ray player, it is not that impressive. I recently watched two Sony 4K TVs next to each other play the same material simultaneously. Both looked mouth-wateringly good with the 4K demo feed and were pretty much indistinguishable.Next came the Avengers Blu-ray disc. The earlier Sony 4K TV, the XBR-55X850B, didn't look nearly as good as my Panasonic ST50 plasma from a few years ago. The newer Sony set, the XBR-55X900A, looked absolutely phenomenal. In fact, I liked it just as much as any of my plasma TVs. Contrast and colors were natural, it was extremely sharp and detailed, and I did not notice any problems with motion. I'd buy an XBR-X900A series TV in a heartbeat if I needed a new, top-of-the-line television. It has amazing quality with the program sources we have today and the potential to play the 4K material of tomorrow.I encourage you to consider a 4K set, as I think there is something to the new standard and believe it will eventually be successful. To make sure you get a TV you will be happy with, bring your own favorite Blu-ray movie to the store and ask them to play it for you so you can see what the TV looks like with material you are familiar with.