Turbine vents versus ridge vents

Bids for our roof (4/12 pitch in Minneapolis) disagree on venting needed.
Currently have 2 turbine vents and several smaller box vents. Contractors agreed we have enough soffit vents but they need to be cleaned.

One says we need to pull out the turbine vents and install ridge vent, the other said that 2 more turbines and a couple of “L 750”(?) or similar vents would do the job.

The bid with the ridge vent was considerably higher and the budget is tight.
Any reason why one would be better than the other?

I liek the turbines, Do not mix turbines with L 750’s. This will cut the convection from eave to ridge if you do.

NEED ridge vent? Never needed it before. Ridge vent is a viable vent, but also sort of a luxury item as far as roofing is concerned.

I know the proper number of sq in, inch for inch, is more productive with properly functioning turbines with a balance ventilation system.

To be honest with you i would go and find a contractor that knows ventilation. Aaron is correct when saying mixing vents is a no no. Along with what Aaron said the turbines will turn the static 750’s into intakes and then you are really in trouble when it rains or snows. I agree with the ridge vent comment also. You dont really need it. Im a fan of turbines but many people think they look ugly. They work better than any other vent out there that uses zero power.