These days, 3D TV sets aren't all that pricey anymore. Come the 2011 holiday season, you'll see 3D TVs even in the bargain-basement listings, with big-name manufacturers such as LG and Samsung releasing 47-inch 3D plasma sets for as low as $600 to $700.

What are you paying for when you choose a pricier set? We tested three active-shutter 3D TVs from different manufacturers--of varying display types and prices--in order to determine whether 3D enthusiasts should pay more for a prettier picture.

The verdict: You should.

Meet the 3D TVs

We chose the 43-inch plasma Samsung PN43D490 ($550) for our low-priced TV, the 50-inch plasma LG Infinia 50PZ950 ($1500) for our midrange model, and the 46-inch LED-backlit Sony KDL-46HX820 ($2000) for our highest-end set. With this mix of TVs, we were able to tease out the factors that make the difference between a 3D movie and a 3D headache, including the screen size, display technology, refresh rate, and so on.

Keep in mind that all three sets require active-shutter glasses, not polarized 3D glasses (read our "Active 3D vs. Passive 3D" feature for our comparative testing of the two types of 3D technology). Active-shutter 3D relies on expensive, powered glasses that alternately block the image from reaching your left eye and right eye, which forces your brain to put together two separate images from a slightly different perspective to create the 3D illusion.

Generally speaking, active-shutter 3D display technology should favor plasma TVs over LCD/LED sets, because plasmas can refresh the image more quickly and make the active-shutter 3D effect look better. In our testing, however, we've found that 3D performance varies widely from set to set--and since the LED-backlit Sony 46HX820 boasts a competitive 480Hz refresh rate, it's no slouch next to a plasma set.

Test Scene 1: 'Viperwolves'

We used three scenes from the Avatar 3D Blu-ray to put these sets through their paces: Scene 10 ("Viperwolves"), Scene 11 ("Neytiri"), and Scene 14 ("Hallelujah Mountains").

The "Viperwolves" scene depicts Jake (in his Na'vi avatar form) fighting a pack of viperwolves at night. It's an up-close scene with a lot of foreground 3D effects--arrows flying here and there, underbrush obstructing the camera, and fast-motion scenes where viperwolves burst from the background into the foreground (and vice versa). During close-in shots with a pronounced foreground and background, 3D display tech has the potential to look downright stunning; but if it isn't done well, it's a recipe for an instant headache. Also, "Viperwolves" is a nighttime scene with a lot of contrast, so it’s a good test for determining whether a TV's contrast suffers significantly in 3D.

Samsung PN43D490: Watching this scene was rather frustrating. All of the foreground effects--the vegetation, the flames, and the like--looked flickery, and at certain times we noticed a mild case of "crosstalk," which made it look as if we had double vision. Make no mistake, the 3D effect was certainly present, but in a headache-inducing way, not a good way. Color and contrast appear reasonably good as long as you're watching in a pitch-black room (which is ideal for 3D and plasma TVs, of course), but if your room has too much light, you'll struggle to see the darker parts of this scene due to the reflection on the TV's glass screen.

LG 50PZ950: Overall, "Viperwolves" looked great on this set. We noticed mild crosstalk in the foreground plants, but the rest of the scene seemed crisp, clear, and deep. 3D tends to look its best when it's subtly adding depth to the scene rather than randomly throwing things into the foreground, and the 50PZ950 did a good job of showing that. The colors were vivid, which looked good but tended to counteract some of the ominous darkness of the scene.

Sony 46HX820: "Viperwolves" looked good on the 46HX820, albeit slightly less deep than on the LG 50PZ950. One judge commented that she found the motion sequences rather jarring, and that she felt a little queasy while watching; another judge had neither problem. This scene did show off the 46HX820's contrast range quite nicely, though--Sony's set was the only one of the three to do justice to the dimly lit portions of the scene without losing detail.

Test Scene 2: 'Neytiri'

"Neytiri" is the scene immediately following "Viperwolves." A slow-paced scene, "Neytiri" has a mix of close shots and atmospheric shots that show off the complexity of the Pandora jungle. It culminates with Jake being covered by the seeds of Eywa--floaty jellyfish-looking thingies that, when done right, appear to pop out of the screen.

Samsung PN43D490: The PN43D490 did fairly well with "Neytiri," producing a subtle sense of depth between Jake and Neytiri during their initial encounter. The shots that showed off the Pandora jungle were a bit dizzying, and the scene with the seeds floating around Jake looked a bit less crisp on this set than on the others. All in all, Samsung's TV did a decent job of showing a 3D image without offending the senses.

LG 50PZ950: This scene truly demonstrated the 50PZ950's 3D ability. The background shots appeared deeper than in any other 3D scene we had ever watched, the seeds really popped out while showing only the slightest hints of crosstalk, and the overall image seemed crisp and colorful. The atmospheric shots took advantage of the 50PZ950's larger screen to create a more immersive image.

Sony 46HX820: Overall, the 46HX820 looked great in this scene, with little crosstalk and plenty of depth, although not quite as much depth as we saw on the LG model. The seeds popped out without being obnoxious, and while the 3D effect was more pronounced on the LG set, the image looked clearer and more colorful on the Sony TV.

Test Scene 3: 'Hallelujah Mountains'

In "Hallelujah Mountains" a helicopter passes through the floating mountains of Pandora. It's shot from very far out, and there isn't a whole lot in the foreground, so we included it to see how well each TV handles 3D depth in a scene that could look flat on some sets.

Samsung PN43D490: "Hallelujah Mountains" was a veritable torture test for the PN43D490's 3D effects. The scene was flat on this set, and the colors were slightly washed out. No hard feelings, PN43D490--that's exactly why we picked this scene.

LG 50PZ950: On LG's TV this scene seemed pretty flat, though a few elements made this set stand out--namely, a few shots brought the helicopter cockpit into the foreground to make the image look deeper. It looked okay, not great.

Sony 46HX820: The jury was split on this one. One judge thought this scene on the 46HX820 was just as flat as on the PN43D490, while another thought it looked the best out of the three (although still very subtle in comparison with the other two scenes). While the 46HX820 was the best at bringing out details like the smudges on the helicopter's cockpit glass, such details don't always contribute to the "3D-ness" of the image.

Conclusion: What Makes for a Good 3D TV?

Even though you can buy a 3D TV for cheap, our testing makes it pretty clear that you get what you pay for. Image-quality factors such as refresh rate, image detail, color accuracy, and contrast level still matter once you put the 3D glasses on, and even if your cheaper TV supports 3D, that doesn't mean it'll make the effect look good. Samsung's PN43D490 managed a respectable showing against TVs that are three to four times as expensive, but it doesn't take a hard-core home theater enthusiast to appreciate the difference between the PN43D490 and the two pricier sets.

The overall 3D performance results of the LG 50PZ950 and the Sony KDL-46HX820 were fairly close, with the LG model generally producing a better 3D effect and the Sony set edging it out in overall image quality. Considering that the LG is a bigger set priced $500 less than the Sony model, value-minded 3D fans would do well to consider it. Even if you're not sold on either set, however, the LG shows that when it comes to 3D effects, a big high-end plasma is your best bet for the money.

This story, "3D TV: You Get What You Pay For" was originally published by PCWorld .