Here's an update to my (nearly) free MDA from T-Mobile Experience.
Surprisingly, it is mostly positive! From ordering my phone and plan, modifying the plan, canceling my old plan, receiving the MDA by mail, and setting up the MDA with WiFi and (after a minor blip) Bluetooth with ActiveSync, internet browsing, and Skypeout service. I hope others who have an MDA can benefit from my positive experiences.

Before Receiving My MDA.
Ordering from LetsTalk.com couldn't have been easier. As usual (and this is the third phone and plan I've purchased from them), their online storefront had a decent, usable interface, and their selection was wide and varied. They carry all the major carriers and practically every phone out there. As I understand it, they have phones that even the carriers no longer stock. Also, their customer service was easy to get ahold of by telephone.
First a little history: I have been out of contract with T-Mobile for some months, so I really wanted to wait for the next great phone deal. I hate to pay premium prices for the latest gadget and I prefer legacy systems that have all the bugs worked out. So, when this deal came along for a free (or $74 for me, since I declined to add a $30/mo data plan) MDA, I jumped at it. My old plan provided me 1500 minutes/month for only $39.99/month, the new 2-year plan was for an MDA and 1000 minutes/month, so I only lost 500 minutes/month, but gain a great new PDA phone! But wait, there's more! A few days after my order, I checked T-Mobile's website and found that they've re-introduced their 1500 minutes/month plan again at $39.99/month; my old grandfathered in plan! Naturally, I called T-Mobile (they had already received the new activated plan from LetsTalk, which is just another number to my current account with them) who were glad to modify the same plan for the new 1500 minutes/month. No additional costs or contract extensions! You really do "Get More" with T-Mobile.
Just recently, I received a $25 reward credit from LetsTalk, which I can apply to accessories. I equate this to my brand new MDA costing me only $49! What a great deal!
At Last, the MDA Arrives!
Exactly as promised the phone arrives via UPS; perfectly new, updated, and fully charged by
LetsTalk.com. Apparently, LetsTalk.com does all the upgrades and prep work, so all I needed to do was customize the phone. All those downloaded upgrades I had gotten, because of the articles I read were unnecessary!
Phone Setup
Setting up simply included a quick read of the tiny picture poster that came with the phone: opening the back cover, sliding in the SIM, popping in the battery, replacing the cover, and powering up. After about 5 minutes, Windows Mobile came on crisp and clean, with all the T-Mobile updates installed during the initial sequencing via GPRS or Edge (I'm not sure, but it was quick). A quick call, one to my new phone and one from my new phone verified that phone half of the dual-processor worked great.
WiFi
Going through the Comm Manager, I activated the WiFi. Then going to the settings for the WLan, network card UI, I found my WiFi listed amongst all 15 of my neighbors (why do we need DSL, when only one is required?), and put in my WPA-PSK. Bingo, bongo, boingo, I'm connected. And yes, the device prefers WiFi, since it will not connect to your data service if it's present. My trick was to put in my old, deceased SIM, so that there would be no unintended hookup to my new phone plan.
ActiveSync
T-Mobile provided a new download for ActiveSync 4.5 via Microsoft.com. I installed it before going further. This was surprisingly easy and successful.
Bluetooth
Using a Linksys BT-120 on my Winbook 330 Laptop to connect to my MDA posed only a small blip. Like many Bluetooth dongles, a CD with installation instructions came with it. If you have WindowsXP, skip the CD installation and just use WindowsXP's utilities. I discovered that WindowsXP is Bluetooth ready, such that you only need to plug in the dongle to any open USB port (remember to use the same port each time, though). If you install the dongle's OEM software, like I did initially, then it may not work right.
Secondly, I discovered that ActiveSync's help file for connecting through Bluetooth made no mention of using the Bluetooth utilities, on both the PC and MDA, to find Bluetooth Services available from each device. This is vital for setting up a serial COM port on each device, for each to discover the other. This is after you've paired (or partnered in Windowsese) the two devices, by making both discoverable (which you can turn off after the partnership has been established once). Otherwise, ActiveSync's help file was useful for the basic steps.
As for ActiveSync, you simply have to tell it to connect via Bluetooth. I set this up to automatically sync when the PC (this can be set up for multiple PCs too) is discovered. As mentioned in HTC Wizard and Skype forums, ActiveSync needs to be disconnected (not off), before Skype will recognize a live WiFi connection!
SkypeOut Works Great
I next installed Skype by downloading the .cab file directly to my brand-new, Sandisk 2GB miniSD card (which was delivered the day before for a mere $23 via an Amazon.com seller). I ran the installation flawlessly, signed into Skype, and presto! all my numbers and account stuff appeared similar to my PC UI. I made a call and it was just as clear as my PC calls for SkypeOut (equivalent to a pretty decent cellphone call). Now I can travel the world making calls via WiFi, and saving loads of money (SkypeOut gives you unlimited calls to any phone in the US/Canada for only $30/year - yeah, I missed out on the $14.95/year in January deal)!
Miscellaneous and Registry Tweaks
I've performed some minor UI tweaks and a few registry tweaks. In the start menu, I simply picked the seven most used programs through personal settings interface. For my Skype calls and playing sound and visual multimedia, I installed the Bluetooth Audio executable, btaudio, to allow me to play sound through the bluetooth headset. MDA/Wizard users have always wanted to use their bluetooth headsets for other reasons besides making phone calls; btaudio fixes this easily! The problem most users have with the installation is creating the shortcut. Remember, you can use Total Commander (the best and must-have MDA utility; make sure you have this) to select the btaudio downloads stored on your storage card, then copy/move the selected file (btaudiotoggle.exe). Go to the \Windows\Start Menu\ folder and paste a shortcut there via Total Commander's menu. There is a thread about this btaudio issue you should refer to at the HTCWiz website here. I modified only one button (the one with the envelope) for opening up MIDlet Manager (another must-have), where I keep my Gmail app. Many want to have a close all memory button, but I still use the End-call key for this, since I've not run into any memory issues yet, even when connected via Bluetooth and WiFi and on a Skype call!
Summary
The one thing I'd take away from this positive experience is to get your ducks in a row. I made sure I cleaned up my Outlook Contacts list and put them in the exact order it should be before synching the MDA to my PC. I also read the entire online T-Mobile PDF manual of the MDA, which you can download from T-Mobile. It's a much larger manual than the one that comes with the MDA. It certainly gave me a heads up. I also spent quite a few days poring over the various threads from HTCWizardWeb.net and the Skype forums. I've learned alot about optimizing and customizing my MDA to fit all my personal needs here, that I was compelled to share the answers with other MDA/Wizard users. I notice that the helpful forums can be confusing to newbies, since not everyone uses proper grammar; very few tech-fans can write literately. I certainly hope I'm doing a decent job here. Also, I realize alot of contributors are writing on the fly on their MDAs, and are not editing themselves too well.
As for my MDA, currently I can:

• make mobile calls - voice dialed, bluetooth, and normal ones
• make free or super cheap, clear Skype WiFi calls to any phone on Earth, with my bluetooth headset as well
• play 2-way audio through my bluetooth headset, including voice dialing
• run Java PDA apps through MIDlet Manager or using J9
• surf both WAP and normal websites using IEM - not a tweak, but really cool when I'm in bed or out on the town
• use the amazingly crisp Google Maps
• use the built-in MS apps like the Contacts list to call or email through the phone or Skype
• enjoy the improved ergonomics with tweaks that add new indicators for the keyboard, blinking lights, keeping lights off, saving installation cabs, etc. Too many little things that make using the MDA easier and more pleasurable
• more to come as I continue adding new tweaks...