I have an 05 KLR. Last winter before I bought the KLR, I did a lot of research like you are doing.
1) I decided I wanted the larger fuel tank on the KLR. I rode in Colorado last summer with a friend who has a KTM 6 days 620. He had to carry extra gas in a can and found that to be a pain, especially where there are not many fuel stations. There were some days, we did not make it to our destination because he ran short on fuel and had to turn around.
2) More comfortable seat. At the end of the day, he was saddle sore too!!
3) More accessory options. totallywiredcycles.com klr650.com - just to name a few.
4) I also like the Liquid cooled motor in the KLR versus the air cooled DR. I never have a problem with overheating.
The DR is definitely more dirt friendly than the KLR. I found if you ride mostly on hardtop and occasionally on dirt, the KLR is the bike for you. If you want more dirt riding than hardtop, the DR is the choice. I rode 8000 miles last year and found this bike to be a great all around bike!!