I rode in a nice 550 fancy executive bus last week. I asked the driver why gas and not diesel. He laughed said he got that question all the time. He said they had 4 gassers and two Diesels. He said both Diesels are in the shop for any number of mechanical issues every few weeks. The 2014 we were in had 210,000 miles and he said its only gone in for basic service stuff. Nice truck. Our Disney week the local bus company supporting our hotel had a brand new fleet of three good looking International diesel monsters. Day three all three were broke down. A old you guessed it gasser 550 shows up joking with the driver I asked what the mileage was on the trusty back up bus. 368,000 miles.
I do think there is some teething problems in the 2010-15yrs when makers were behind the curve in diesel engine development.