I don't like either one. I don't like Chevron Delo 400 either. All of these three oils make my '95 7.3 liter turbo diesel sound like a washing machine needing a new motor.
Recently, I've been using a mix of Delvac 1300 Plus 15w40 and Delvac Turbo Diesel Truck 5W-40 synthetic (now titled Turbo Diesel Truck 5W-40), as well as Castrol 15w40 Tection Extra, and a syn-blend from Cenex called Maxtron DEO 15w40. Everyone of these three oils (or combinations) makes my 7.3l DIT purr -- and, in comparison with other 15w40s, each significantly smoothes its vibrations.
I will try the Rotella T synthetic 5W-40 for winter time because it has shown some very good UOA results in a variety of diesel applications.
As an aside, the MC 15w40 is quite expensive in our vicinity in relation to Delo, Rotella and Mobil oils. The MC expense has turned me off, but so has the rackety engine noise I experience with its use in comparison to the relatively quiet operation achieved with the other oils cited above.
FWIW . . .