[gr8fl4porsche]

Drywall is the only way to truly get a finished look.
Without it, your basement will look like a basement as opposed to another level of the house.

Ceiling tiles are too commercial.

Painting of the open ceiling is fine but is not finished.

Drywall to your highest points and build soffits around your low points. If it takes multiple soffits to keep your ceiling height maximized, so be it. I am finishing mine currently and have many levels of ceiling heights. Turned out very cool. Very timely and costly, but very cool. Lots of angles and different heights creates visual interest.