I read somewhere that it is easier to take cab off than engine out, but I do not know details.
I guess it is all about turbo and exhaust manifold, which is pain to disconnect, as it is sqeezed between engine and firewall and some screws you must target blindly, even harder to put together later.
By taking cab off you have all disconnect points more or less within reach. I guess.
At least and not last, by taking cab off you can address frame rust and exhaust manifold leaks easier, so my vote goes to cab off against engine out.