Need help please 2014 to 2016 Mx 13 vs Cummins isx reliability

[Cummins5555]

My main cinders is reliablility because I got the money and know how and I’m getting the extended warranty for engine and all the emissions but is the Mx13 have the problems the Cummins does I have the money and all that but if ur smart I’d rather not spend it and make the best miles per gallon so I’m looking for help on if the Paccar is more reliable the the isx Cummins or not and I’m doing just fine as a owner operater thanks for your concern