I do not have a Duke III but I did have a 2007 690SM for 9500 great miles. Only problem was the stalling which an 08 should not have due to the different ECU's. I would change the oil every 2000 miles though. I did about 70 miles of commuting for 10 months in everything from 105 degs down to 8 degs and she was great. Only problem now is what to replace her with cause the KTM does not react well to a cager doing a left turn in front of you! You will love the bike!
Honda 2007 CRF150R
KTM 2008 690 Duke 43,000 miles baby!
KTM 2011 530 EXC/SMR
Aprilia 2007 SXV 550
KTM 2008 300 XCW