Dr. Bob-
Unlike most of the other respondents. I have actually owned and ridden both bikes (well not exactly, I had a Weestrom and and have a 995 Tiger). I must say that the DL did everything a bike was supposed to do quite well, however it was not inspirational (at the risk of offending nearly everyone, I usually compare it to a Toyota Camry). I have never given a second thought to the decision to trade it in on the Scrambler and keep the Tiger.
The main difference, as some people have pointed out, is the engine. There is no describing the feel of the triple especially in comparison to the V-twin.
There was no difference in reliability, the VStrom got better gas mileage by about 5% (smaller engine?), they both handled the twisties the same, the Tiger was waaaaay quicker (again smaller engine?), both had problems with wind noise, and the Triumph fit and finish is better.
Hope that helps,
Fred