I was asked the other day what I thought about the Tmobile Dash aka (HTC Excalibur) I had actually looked at the dash when I first looked at the Nokia E61 since it had some of the features I wanted - Wi-Fi, QWERTY, etc. While the device looks ok, it resembles a blackberry too much because of the black casing and round edges. The keyboard makes it look a bit like a toy due to the colors and shiny finish on them.. the keys look like they are very tight together and there is no space in between which could make it hard to type..
The dash does have a 1.3 mp camera which is something the e61 lacks but I dont miss it at all. One of the good things about buying this locked down tmobile phone is that it comes preloaded with myFaves and a IM client in addition to your usual windows mobile applications.
The Dash is a bit smaller than The motorola Q, and while it doesnt have 3G it does have EDGE and Wi-Fi. I had read other reviews and seems that one frustrating fact is the lack of data signal even when you have full bars you are not able to jump on the internet, and bluetooth connectivity has been said to be a challenge to pair with anything.
One cool point for the Dash is that if you have a data plan that includes the Wi-Fi your dash will automatically sign you into the hotspot. The phone is quadband which makes it overseas ready and helps it get as much signal as possible here in the US where t-mobile is known to suffer..
In conclusion, I think the dash is an ok smart phone because it has Wi-Fi, but its still a Tmobile phone (the voice quality and reception on tmobile is pretty bad from my personal expereince) it also runs on Windows Mobile OS (which means it will crash alot) and the desing and look of it is not cutting edge enough for me as it should be because of the kind of smart phone it is. The guys @ engadget have a good review of the dash as well here