T-Mobile's first Windows Phone 7 device - the HTC HD7 - is available today for $199.99 on contract.  It's a nice device, and is one of my personal favorites out of the first batch of WP7 devices.  The HD7 launches on the heels of the T-Mobile G2 and myTouch 4G, two high-end Android devices that are capable of utilizing the carrier's HSPA+ (or "4G," as they're calling it) technology for a supercharged data experience.  I've spent the weekend using the HD7, and here's what I've discovered thus far:

• The HD7 ships in a similar box as the T-Mobile G2 and comes with an AC adapter module, USB cable, headset with in-line microphone, and instruction manuals. 
• Pictures don't do it justice; the phone is absolutely gorgeous.  The metal kickstand that pops out from the camera is a nice touch, and the combination of metal, glass, grey accents, and chrome make the device look sleek and lightweight.

• I'm having issues with the power button.  After a few days of use, the power button has recessed so far into the body that it has become a challenge to press.  More than once, I've had to press the power button two or three times before it would spring to life.
• HD7 packs a 1 GHz (Snapdragon) processor, 16 GB of internal memory (no microSD card slot here), stereo speakers, 5.0-megapixel camera with HD video recording, and Wi-Fi connectivity.  The HD7 joins the EVO and HD2 in offering a 4.3-inch display, though it's a standard LCD.  I can't say that the lack of a "super" display bothered me - I've been pleased with it thus far - but those used to AMOLED or Retina displays will notice a difference.
• Windows Phone 7 is exceptionally responsive on the HD7 ("freakishly responsive, as I said in a video).  Granted, a majority of that speed comes from the fact that Windows Phone 7 doesn't multitask, but the overall fluidity of Windows Phone 7 is fantastic.  From scrolling through menus to browsing the web to searching for contacts, I can't recall a single time that I experienced lag.  The transition effects - those pretty little things that make moving from one application to another seamless - are gorgeous.
• On multitasking versus fluidity, it becomes an issue of what matters more to you - multitasking with occasional lag, or no multitasking with consistently fluid performance.  Surprisingly, I didn't find myself missing the ability to multitask, and as of right now (my opinions change regularly), I would take the fluid experience over the ability to multitask.  If you've seen the recent cluster of Microsoft commercials, you'll realize that they're positioning Windows Phone 7 in that manner.
• It's a minor Windows Phone 7 issue, but it irritates me that the signal strength indicator and battery meter aren't permanently displayed.  Instead, you have to swipe the top of the screen each time you want to see the information.  It flows well with the minimalistic design of Windows Phone 7, but the option to display it regularly would be nice.

• The 5-megapixel camera isn't great.  It works well enough when taking shots outside, but indoors or in low-lit situations, I found it to be a bit blurry.  I'm working with the HD video now and will have results in the full review.
• I've been pleased with call quality thus far.  Callers sound loud and clear, and I've been told that call quality is good on the opposite end.  The speakerphone is loud, and while in a T-Mobile dead zone in uptown Charlotte, I was able to hold a call, despite choppiness.
• HTC, T-Mobile, and perhaps Microsoft get points off for failing to make the HD7 an HSPA+ ("4G") device.  That's like launching an Aston Martin with an inline-four engine.  The phone screams "high-end," but the network technology tells another story.  The HD7 is also missing the Mobile Hotspot feature that the myTouch 4G offers.
• I spent the weekend using the HD7 as my primary device, and was disappointed with the battery life.  With light to moderate use including calling, text messaging, web browsing, use of the Marketplace, and light use of some downloaded apps, I struggled to make it through each day.  If I'm having battery issues on the weekend, I'm a bit concerned to see what battery life is like during the week, when I use my phone significantly more.

Check out Aaron's full HTC HD7 review in video form!