These sorts of shooters generally are more complicated to build and tune, however with the right set up they theoretically have a ton of flexibility in terms of shot trajectory. An extra spinning wheel introduces more dynamic variables into the process than a fixed hood would, and I have yet to see a situation where the extra variability in shots has really been a significant advantage over fixed hoods.
Simpler and arguably easier to tune at its most simple form, that being a fixed hood and shooting from one position on the field. But with a bit more work it can be tuned to shoot from a pretty broad range even without an adjusting hood. To a certain extent, different predetermined RPM settings will allow you to shoot from a longer distance or closer up.
Primary variables to consider for both of these shooters:
Exit Angle: What angle does the ball exit the hood at?
Wheel Wrap: How far around the wheel does the ball travel before exiting?
Hood Material: Self explanatory
Wheel Material: Self explanatory
I would say the most important variables out of these four to focus on when fine tuning is the material of the hood, the RPM of the flywheel, and the exit angle of the ball.