Yes, I spotted sweat on the upper lip of Kevin Spacey's fictitious vice president while streaming Netflix's 'House of Cards' on a new 65-inch Ultra HD television from Samsung. It's the kind of discovery you can make with a technology that's pushing for the mainstream this year: televisions that have four times as many pixels as the industry-standard high definition. That's more pixels than some cinema projectors, packed in so tight they just melt away.

Ultra HD (sometimes called '4K') televisions have been around for more than a year, but until now held limited appeal. Prices were stratospheric, making it hard to justify a bump in clarity. Now Ultra HD prices are flying closer to Earth: Brand-name sets start below $2,500, and $5,000 will get you Samsung's top 65-inch curved-screen HU9000, which I tested this week.

If you're the kind of connoisseur who wants to be first to see Mr. Spacey sweat, it finally makes sense to make the leap to an Ultra HD television. The arrival of the new Ultra HD sets is part of a home-theater renaissance that's making the tube cool again and making me consider an upgrade.

But to enjoy the full benefits of UHD, you'll need a fast broadband connection, and possibly a couch that's much closer to your TV.

The biggest reason to finally give Ultra HD a look has to do with content. Previously, there was very little made-for-UHD video, and -- even worse -- no good way to deliver its giant files to homes.

Though there's still no TV programming broadcast in UHD -- and none on the way, for the time being -- the equation changes this spring when Samsung, Sony, LG and Vizio couple their Ultra HD TVs with streamed content from the Internet: UHD programs like 'House of Cards' from Netflix, with more shows and films on the way from Amazon.com, M-Go and Comcast.

So here's the $5,000 question: What can you really see with Ultra HD? On the Samsung HU9000, I experienced a qualitatively better image both with UHD content and regular Blu-ray HD content that the TV 'upscaled' to Ultra HD. That said, it isn't the kind of transformative experience you had the first time you saw a sporting event in regular HD.

What you do get with Ultra HD is a sense of detail that sneaks up on you, especially on wide shots. For example, an overhead scene at the beginning of the film 'World War Z' looks like ant-sized people are scrambling around on my HDTV. But in Ultra HD, you can see, in horrifying detail, those poor souls being tackled by zombies.

With that kind of resolution, sitting closer to the screen makes you feel much more like you're in on the action. In fact, some argue you must sit closer -- or buy a larger TV -- for the eye to benefit from the extra resolution. You'll likely want to rearrange the furniture. For the 65-inch set I tested, I scooted my couch up until it was just 6 feet away. Get too close, though, and you'll start to get the same dizzying feeling you get in the front row of a movie theater.

The curved screen, a feature I was skeptical about, was actually pretty nice for creating an immersive experience, especially with a close-up couch. Probably its key benefit, however, was minimizing glare during daylight hours. It adds about $1,000 onto the price of a basic Ultra HD set.

Samsung makes fantastic screens, but the rest of the package is mixed. The sound built into the HU9000 model I tested was anemic, but presumably anybody buying such a big TV would have a sound system. Samsung's 'SmartTV' interface has been improved for switching between live TV and streaming, but still isn't as simple as set-top boxes like the TiVo Roamio.

It's true, televisions historically haven't been a great technology for early adopters. Battles over standards and formats have left many in the lurch. Samsung put the TV's brains in an external box that can be easily upgraded. This promises to considerably extend the life of a TV you buy today, if you're willing to shell out $400 or so for next year's 'evolution kit.'

Netflix, the first premium service to deliver UHD video over the Internet, has accomplished an impressive feat in making it work over broadband (at no additional cost to subscribers). Some early testers report image quality problems in darker patches, but 'House of Cards' looked fine to me. And Netflix's chief product officer Neil Hunt told me the quality shouldn't suffer as more people get Ultra HD TVs and all try to stream at the same time.

It won't work for everyone because Netflix requires broadband speed of at least 16 megabits to sustain the Ultra HD connection. That may be easy for cable connections like my Comcast hookup in San Francisco, but it's good to find out your own carrier's top speed.

As for Netflix's competition, it's not yet clear how much Amazon and M-Go will charge for Ultra HD streaming, or how well they'll work. (Those services weren't ready during my test, and Samsung's TV software can't yet play the Ultra HD content now available on YouTube.)

Netflix will push UHD because it wants its streaming technology to leapfrog physical media and traditional broadcasters. But expect Hollywood's own UHD content to arrive in a trickle, rather than a tsunami. Most movies and shows today still aren't shot with cameras that record in UHD. While that's changing -- and film tends to be greater resolution than typical high-def -- some directors still prefer the look of shots taken with older cameras.

Today, there aren't even any UHD videogames or major sports coverage. To supplement the streams from Netflix and others, Samsung is selling a $299 add-on device loaded with five Ultra HD movies. Sony has one for $700 with 50 movies. Either way, these feel like extras they should throw in free, like floor mats in a new car.

Some TV technologies like 3-D have turned out to be gimmicks. But Ultra HD is different because it shifts our perception fundamentally, from the pixels to the pictures. That's why, despite today's challenges, Ultra HD is inevitable on the largest screens in our homes. It's better for movie nights and for displaying text and other information. You just have to decide when you want to make the leap.