Sully2- I traded my 2000 36' Dp on a 24'Thor Siesta with the Mercedes 6cyl engine in June of this year. Now have 8000 miles with no problems. Consistently 16mpg, smooth running and easy to handle. Florida to Niagara and just returned from the Blue Ridge Parkway. Seldom use the toad, just not necessary. Available power has not been a problem.
While Freightliner seemed to support DIY maintenance, Mercedes seems to want more control. Maintenance overall is simpler.
Weight ratings on the sprinter chassis are close. My unit basic weight is just under 10K,(full fuel & propane + driver) GVWR is 11030 GCWR is 15250. Rated to tow 5000# but if at GVWR only 4200# is available. MY toad is also just under 4000# and tows easily.