Of the two models you mention, I would go for the DK35 for the extra power, and better ergonomics. The LK3054 has been updated with more room in the operator's area.
Neither of the prices are bad, the DK35 price is pretty good if all looks as though the 20 hours are actual.
Prices will be going up October 1 by between 2% and 5% with the largest increase being on the DK65 which will get a new 4 cyl. Perkins instead of the current 3 cyl. I'm not sure what that will mean for the new prices on either of these models, but check out that DK35 really well. If you can, get a quote on the exact same model new, with full warranty and all the same equipment. It may be that you'll want to go the extra to have a brand new machine with all the warranty. Keep in mind that if the tractor was originally bought before January, 2003, the warranty is not transferable. John