Well, when you read the T-Mobile forums and every other post is about the MDA or SDA, you learn a lot.
Well, the MDA is off to a little rough start. Many people have been having problem with the recepetion or just buggy firmware. Some people say their MDAs are working flawlessly. It's basically a hit or miss, you get a working unit that works effortlessly, or you get a dud basically. If you absolutely need the MDA for unit integration, go for it. Just be aware that issues might occur. If you just really want the MDA for internet and e-mail integration, you might be better off just getting a phone with Bluetooth and a good PDA with Bluetooth for sure and maybe WiFi. That way if you have a problem with the phone, you don't lose your life that's on the MDA. That's just my personal opinion. Hope this helps to the original poster!