What are the pros and cons of soffit vents vs. roof vents?
Soffit

Pros


Vent easier to install
In heavy snow areas, not likely to be blocked


Cons


Soffits are designed for intake, so it's possible the air will be sucked back into the attic
Moist air can collect under the soffit


Roof

Pros


Heat and moisture want to rise
Keeps moisture away from walls, windows, siding


Cons


Can be blocked with heavy snow
More difficult install


I don't think it's that difficult to install a roof vent - this is a pretty good video