Jerry Ordway's Shazam was one of my son's favourites when he was little, and I also have fond memories of the series because I read it to him until he eventually read it to me.

I liked Gil Kane's Mar-Vell in its day, and I still think it's visually attractive, but the writing has not held up well:

But I'm not an especially big fan of any Captain Marvel, so I'll give my vote to that kooky "Split!" version.