I've had Both
I have owned BMW's since 1978, I now own a DL650K7. The old airhead Beemers were very reliable and easy to work on. The new ones are costly and not easily worked on yourself and are NOT RELIABLE. New Beemers have a lot of drive train issues, which if your under warranty are not expensive, however out of warranty they are way out of sight.
Use 4 qts of oil and filter every 3k miles
Tranny & final drive take approx. 1 qt of tranny fluid every 5k-10k miles depending on your preference in up keep.
Valve adjustments every 6K miles
Clutch & brake fluid changed every 2 years ($150)
Final drive seals every 25,000 miles and hope the bearing don't crap out.
Total cost at dealers run about $400+ every 6K miles.
Uses 3 qts of oil and filter for engine and drive train every 3K.
Valve adjustment every 14,500 miles
Spark plugs every 7K
Chain and sprockets every 20,000 miles
Brake fluid change every 2 years
Coolant flush and replace every 2 years.
Total cost at dealers is about $400 every 14,500 miles
So in reality with the DL you will cut your maintenance cost in operation about in half. Other considerations would be the cost of gas. The DL uses the cheapest gas. The BMW's use the most expensive gas. The DL will get better gas mileage, however this is right hand dependent.
Other considerations would be down time for work to be done, dealer location, and of course reliability.
Just my experience. BMW's are getting like Hardleys, don't ride just get a group together to work on them and drink beer. The beer is a good idea, however I'd rather ride than work on a bike.