The main advantage of the new Galaxy over its predecessors is its speed, with the ability to take full advantage of T-Mobile’s upgraded HSPA+ networks (earlier “4G” devices have run at fast speeds, but not the full theoretical maximum network speed, T-Mobile said). The new Galaxy phone, which will launch later this month, also adds a front-facing camera for video chat as well as support for mobile HD television content. T-Mobile won’t say how much it will cost.

In an interview on Tuesday, T-Mobile Senior Vice President Andrew Sherrard made the company’s now-familiar argument that there’s no point having a great phone like the iPhone if you have to have it on its rivals’ networks.

“Why would you upgrade your phone and downgrade your network?” he said, echoing the theme of the company’s recent ads that poke fun at AT&T and, more recently, Verizon.

T-Mobile USA is counting on an aggressive Android roadmap, low prices and its snappy advertising to blunt the fact that it still lacks the iPhone even though T-Mobile subsidiaries abroad are able to sell the device.

“The organization is going back to its roots,” T-Mobile CEO Philip Humm said in a recent interview with Mobilized. “VoiceStream and later T-Mobile really started in the market as a challenger. They started with big buckets of minutes at the time and later with unlimited minutes. These are things which, in a sense, are coming back now.”

In addition to talking about the new Galaxy S 4G, T-Mobile is also offering more details on its planned Honeycomb tablet, the LG G-Slate it announced at the Consumer Electronics Show last month. In addition to supporting T-Mobile’s faster network out of the gate, the G-Slate will have the ability to both display 3-D content (glasses required) and shoot 3-D movies thanks to built-in stereoscopic cameras on the back of the device. Other features include a dual-core 1GHz Nvidia Tegra 2 chip, 32GB of memory and support for Adobe Flash.

However, the company isn’t talking pricing and still won’t be all that specific on timing, saying only that it will ship this spring. I asked if that meant this calendar quarter, and they suggested I think more broadly than that when defining spring, so that gives some hint that we are likely talking April or May.

It seems, though, that T-Mobile wanted to offer at least a few more details on the product ahead of Google’s Honeycomb event on Wednesday, where the company is likely to show off the Motorola Xoom, which is shipping later this month.

T-Mobile isn’t the only one looking to get some news out before its rivals. Earlier on Tuesday, AT&T announced details on its own 4G Android phone–the HTC Inspire 4G. That phone will go on sale Feb. 13 for $99, the carrier said. AT&T had previously showed off that phone, as well as the Motorola Atrix, at CES.

Sleeker than the somewhat boxy G1, the myTouch boasts longer battery life–up to six hours of talk time, one more than its predecessor–a 3.2-megapixel camera, a virtual keyboard that orients automatically from portrait to landscape mode and, more importantly, better customization.

Now that the Android Market has 5,000-strong range of applications, devices like the myTouch offer a more compelling proposition than even before. “No two myTouch devices will be alike,” Andrew Sherrard, vice president at T-Mobile, told News.com. “They will be as unique as the users that own them. What we have found is that once consumers know how to customize a device and they add everything they want on it, they respond very well to having a phone that is specially designed for them.”

Yep, they sure do.