BARCELONA, MOBILE WORLD CONGRESS 2012 — With their new One line-up of devices, HTC is trying to come up with a flagship line of phones that is as synonymous with top-of-the-line tech and high-end quality as Samsung’s Galaxy or Google’s Nexus devices. We had a chance to take all three of their new HTC One phones for a spin, and came away ultimately impressed.

The HTC One series comes in three models: The One X, the One S, and the One V. Although HTC says this is supposed to be their “flagship” line, the real flagship is the X, a 4.7-inch device that is thin and light at just 130 grams, and runs either a 1.5GHz Quad-Core chip or a slightly slower dual-core chip, if paired with LTE. Comically, the version of the One X that ships with LTE is called the One XL, which would give any iPhone owner already smirking at the sheer size of this device a guffaw. An HTC rep, when asked why the XL only came with a dual-core, said that the energy requirements of both a quad-core processor and LTE would “make the phone explode.”

Although the HTC One X is plenty light and plenty fast, what HTC is really pimping with the One X is the new camera sensor: an 8MP affair with an f2.0 aperture that takes great low-light photos. A special section of HTC’s MWC booth was dedicated to taking low-light pictures with the X, and we were impressed, although a lot of the clarity of the images was due to trickery: the colors in the sample scene were designed to take advantage of AMOLED’s tendency towards oversaturation, so people end up marvelling at how good the colors look in low-light when it has nothing to do with the camera, and everything to do with the way AMOLED displays work. Try pulling out your HTC One X at a goth club and see how far you get.

That said, we were still pretty impressed with the camera chip, which HTC says they made themselves. The camera software is also pretty great, in that it allows you to easily take videos, then pull stills out of the video after to find the perfect moment. That’s a great little feature if you have a hyperactive kid.

There’s also a new Music app, which we really liked. Recognizing that most people don’t have a single musiclibrary anymore, but consume music spread across all sorts of services and platforms, HTC’s new Music app puts an umbrella over all the music libraries you have access to, allowing you to drop shortcuts to new music apps in and tracking all your most recently played music across all platforms. Really neat: I wish the Android Music app did this by default.

The One S is a smaller device with the exact same specs as the One X: a 4.3-inch 720p AMOLED display, 1GB of RAM, a quad-core processor, the 8MP camera, and so-on. Unlike the X, it doecsn’t ome in an LTE flavor, and it’s slightly thinner than the X as well. I preferred the feel of this one in my hand, but that has more to do with my preference for non-tablet sized smartphones than anything wrong with the One X.

Finally, there’s the S, HTC’s dual-core, budget flagship Visually, it looks a lot like the HTC Legend, with a little kickstand at the bottom. It’s only got a single-core chip, 4GB of built-in storage, a 3.7-inch WVGA screen and 512MB of RAM, but it still has Ice Cream Sandwich as well as HTC’s new Music and Camera apps. And speaking of the camera, the V has a f2.0 aperture camera as well with great low-light performance, although it only takes 5MP snaps.

Overall, we were pleasantly surprised. We think the HTC One V is a little odd: a budget flagship phone is a weird concept. Still, all of these felt snappy, looked great and took amazing pics, and we hear the battery life is pretty good too. If you’re interested in a top-of-the-line Android smartphone with an amazing camera, the One X or the One S are good choices when they land in April.