Even if you can actually afford one, now is not a good time to buy a TV with 4K resolution. Hold off a few months and better ones will be announced at the Consumer Electronics Show in January, likely with actual HDMI 2.0 inputs, a wider range of screen sizes, and maybe even improved picture quality. They'll probably still be too expensive for mainstream consumption, but they'll be cheaper than the ones available now.
But if you just Want A 4K TV Now, Damn the Caveats! (™), the Samsung UNF9000 series is as a good choice as any. Its picture is superb for an LED-based LCD -- and LCD happens to be the only TV technology that can deliver 4K resolution to the market now. The F9000 offers best-in-class future-proofing, with Samsung's unique Evolution Kit option available to keep its processor, Smart TV suite, and inputs from going obsolete over the next few years.
Now, about those caveats. Anyone buying a 4K/Ultra High-Definition TV of 65 inches or smaller and expecting to see an improvement in detail -- or any other aspect of picture quality -- with normal HD sources will be disappointed. We tested the Samsung UNF9000 and Panasonic TC-P65WT600extensively to look for any such improvement compared with a same-size 1080p TV, and it simply wasn't there.
Meanwhile actual 4K content is as rare as hen's teeth today, and not going mainstream, especially as broadcast TV, for years. Even when a 4K TV plays 4K content, the improvement over a 1080p TV is likely to range from subtle to nonexistent, depending on how close you sit. As difficult as it is to believe when you hear about all those extra pixels mentioned in marketing materials, 4K offers at best marginal real-world improvements on 1080p. See "Why 4K TVs are stupid still" for more.
Speaking of 1080p TVs, Samsung makes an excellent alternative to this one: the UNF8000 series. In just about every way aside from resolution, it's the same as the F9000. It also costs $500 less at 55 inches, and $1,200 less at 65. Until that price delta closes to a couple hundred bucks, 1080p TVs will always offer superior value to 4K TVs for most buyers.
