People buy smartphones for different reasons. Some look for speed, others features, and many are guided by what their friends, family and colleagues own. Some people want a popular smartphone with a big app catalog and others want a handset that is more obscure so it might say something about their personalities. To some, design and build are irrelevant but to many, buying a smartphone is like buying a watch or a fine pen — design, materials and workmanship are just as important as performance.

Let’s not kid ourselves. Some of the most popular smartphones in the world are made of cheap feeling plastic that creaks and squeaks like a child’s toy. Millions of smartphone users simply don’t care about build quality and instead look only at a phone’s performance-related features or the pitch they get at a carrier store. That’s fine, of course, but consumers looking for something more are turned off by shiny, flimsy plastics. When the hand feel of a smartphone is actually improved by the addition of a $15 plastic case, it’s time to look elsewhere.

There are plenty of smartphones that are as well-made as they are capable. LG’s Optimus G is a terrific example. The front and back are smooth glass and the sides are firm plastic. There are no creaks or wobbly plastic buttons, just gorgeous smartphone hardware to compliment fantastic performance.

But as sleek and solid as the Optimus G is, there is another smartphone that outshines it. In fact, it outshines almost every smartphone on the market.

Back in April, I reviewed T-Mobile’s version of the HTC One S. On the phone’s build, I offered nothing but praise: “I am absolutely blown away by the One S in terms of design and build. This smartphone sets the bar for flagship devices in 2012, and I doubt many phones will even approach the One S this year.” But then I took a step back: “As much praise as I gave the design and materials found on the One S, I far prefer the micro-arc oxidized aluminum finish on the international version of the phone.”

It took seven months, but as of November 7th T-Mobile subscribers now have access to this phone in the finish it was meant to be sold in for $149.99 on contract. HTC (2498) calls it an “ultra-matte black Ceramic Metal” finish and further elaborates on the manufacturing process as follows:

The finish is the result of a process called microarc oxidation (MAO) originally developed for use in satellites. This process transforms the surface of the aluminum uni-body into a ceramic, super-dense crystalline structure that is soft and creates a deep black color.

The science surrounding the One S’s black finish is insignificant as far as consumers are concerned. All you really need to know is that this is one of the most beautiful smartphones ever made.

Like Apple’s (AAPL) iPhone 5, the HTC One S features a unibody aluminum case and a build quality that puts other smartphones to shame. The face is mainly comprised of a sheet of oil-resistant Gorilla Glass and aside from glass and aluminum, the only other material on the exterior of the phone is the smooth soft-touch plastic at the top and bottom of the back. This isn’t cheap feeling glossy plastic — it’s nice and solid, and it adds extra grip when using the phone.

The One S is more than just a pretty face and class-leading design. While it doesn’t pack a quad-core chipset like newer Android smartphones, the 1.5GHz dual-core Snapdragon S4 processor and 1GB of RAM provide a smooth user experience most of the time; the performance issues I noted in my review remain in this latest version of the One S. It also packs an 8-megapixel camera with dedicated HTC ImageChip technology that is among the best smartphone cameras on the market, and a 540 x 960-pixel, 4.3-inch Super AMOLED display (256 ppi) that is stunning.

T-Mobile is still going after iPhone users as hard as it can, and it is still tweaking its network in an effort to provide iPhone owners who defect from other carriers with faster service. That faster service pales in comparison to the LTE speeds iPhone 5 owners enjoy on Verizon Wireless (VZ) and AT&T (T), of course, and using an iPhone with T-Mobile’s service means buying it for full price from another carrier, breaking a contract and paying an early termination fee, or waiting until a contract expires before making the switch.

Will T-Mobile ever sell the iPhone directly to its subscribers? There’s no way of knowing right now. Apple has tested iPhones that work on T-Mobile’s network in the past, but at this point we shouldn’t expect anything to launch until the carrier has a widespread LTE network of its own. And even then, a T-Mobile iPhone still isn’t guaranteed.

T-Mobile might never get the iPhone — but in many ways, it already has the next best thing thanks to the One S.