I got my Dash shortly after it came out. I upgraded from another Windows Mobile smartphone (T-Mobile SDA), so I was already familiar with the WM OS and had all my data in Outlook. I was ecstatic when I discovered that T-Mobile made a download available for the Windows Mobile 6.0 and took advantage of it.
I use this type of phone because I got sick of carrying both a PDA and a cell phone, so I don't have a dataplan. I did try it for a few days but didn't really think I would use it enough for it to be worth the cost. It's a great phone for what I use it for! It's super fast, and the keyboard makes text messaging a breeze.
Another reason I purchased this was the ability to use it oversees when traveling. A quick call to T-Mobile and within 24 hours, they emailed the unlocking code. I took my SIM card out and have used in oversees without any problem!
The size is a lot thinner and lighter than a lot of this style of phone. I like the way it navigates better than a Blackberry (even the new ones). The home button makes it easy to get to the main screen from anywhere, and the back button works almost everywhere. One of the annoying things is the jogger bar on the side is used to control volume. I sometimes have trouble getting it to work when I want to adjust the volume and always tap it accidentally when I don't. It does a great job of silencing the phone quickly though even when I don't mean to.
The camera takes decent pictures and videos. I wouldn't give up my real cameras or anything, but it's nice to have in case you find something humorous you want to show off later.
One great feature is being able to use any mp3 file as a ringtone. If you use an actual song, it will just continue playing the song until it goes to voicemail. It transfers files and address book cards to other phones or even send to email or by MMS.
I've had to replace the battery after 1.5 years, but this phone has been good to me. It easily syncs (even with Vista) my data, and comes with all the bells and whistle one could ask for. It is not 3G compatible, but it is EDGE capable and even distinguishes if EDGE or GRPS is currently available.
I use the WiFi at home pretty regularly. The only issue I've had with it getting to work places with odd password or network protection. It's fast and doesn't cost anything more!
The bluetooth has a pretty decent range but kills the battery pretty quickly. I used to leave the bluetooth on all the time, but now I only turn it on when I'm going to use my headset.
I love that I can turn the phone feature off when I'm on a plane so I can still play games or look at my itinerary. That doesn't stop the flight attendants from talking to me about it, but it's a great feature.
The one thing that has driven me crazy since the day I bought it and even after the upgrades is that it ALWAYS vibrates when you turn it on or off. I called T-Mobile about it, and they don't know how to stop it.
Another annoying part is the lack of a headphone only jack. While it's nice that it uses a standard USB cable to charge, which make accessory shopping and sharing a breeze, trying to find headphones for it can be tricky. I bypassed it all together with a pair of bluetooth headphones that I use for running. They make it great because I can put my phone away and change songs, pause, and even answer calls on the headset. I'll have to get a bigger microSD card if I ever want to run a marathon though!
All in all, this is a great phone. The screen tends to get a little dirty, but I use a screen protector anyhow. If you're looking for a phone that does it all and don't want a touch-screen, I highly recommend the Dash.