stormsearcher, I was in a similar process last couple of weeks. Now own a 05 DR650 with the usual mods but took a couple test rides on a wr250r and am picking it up at the dealer's Saturday am. DR is for sale now (Vermont Craigslist).
As others have said DR is low tech, tractor-like power, heavy on nasty trails, reliable and comfortable on the road. I found it hard to ride it over 60mph on the road. The DR does not like to run at high rpm.
The WR250R needs to be ridden like a two-stroke MX bike, lots of revving, the power is up there, not on the bottom. I like the fuel injection, ergos and dirt-ability compared to the DR. On my test rides I got the WR up to 65 mph in no time, 5th and 6th gears are overdrives. Took it into some sandy trails and could flick it around must better than the DR, no surprise here. It fit me good at 6', 230lbs. Shouldn't need too many mods out of the box, maybe skid plate, hand guards, dirtbagz.
I don't think the DR is any quicker than the WRR on the road. The WR is also super smooth, no vibes. It's just plain fun to ride. It isnt a highway machine, but neither is the DR. I'm gonna use it around town and to hit trails as much as I can this summer/fall.
Sounds like you liked the test ride...