I would do the glass cable rail with a kid is just asking for a climb up and over, also how much time does the kid actually spend in that space . A microfiber cloth and some hot water cleans the glass in 30sec.

And, you have kids. So no one is going freak over fingerprints and smudges. Kids grow up, and can be trained to be careful around the glass. You can also use glass panels with texture, an etched pattern, or a design, that will cut down on the appearance of fingerprints.

Glass would be my choice - timeless.

We are using a lot of steel railing painted black with the pickets (balusters) oriented vertically like what you have in the photo. Verticals will discourage kids from climbing unlike horizontals. Using smaller sized newel, rails and pickets won't do much to obstruct your view. Good luck!