Upgrading, Which is a better Route? a local 4yrs polytechnic diploma OR a private degree 3yrs?

Considering upgrading.
suppose you have a private diploma.

Which is a better Route now?
A: a local part-time 4yrs polytechnic diploma
B: a private part-time degree 3yrs?

note that salary, opportunity are main factors for upgrading.

Do share your experience or reasons for the choice.
thanks!