Which engine is better

Your opening a can of worms. If the engine has been taken care of correctly, all engines are good.
Otherwise its like asking what fruit is better? Apple, oranges or bananas

 

Exactly, id take my 99 1.75+ million 3406e over almost any unknown enginesimply since im the only driver since it was rebuilt

 

I'd go CAT. Those ISX aren't such a great engine IMO. EGR is the dealbreaker for me.

 

Thats not important , but whats the best engine

 

The best engine can be a money pit next week ...

 

And if both of these engines have been taken care of equally, then one has twice as much life left in it.

 

Cummins.

The only good engine CAT ever made was the 3406C/E.

 

That just goes to show you right there which has more resale value... you get what you pay for

 

At least a Cat will usually break a million without dropping a liner.