I didn't think I'd care much about the extra 2 inches, but I use it all the time. Being able to switch between 16, 17, and 18 inches makes it much easier to wear with different necklines.
I've worn it with a plain tee and also with a nicer outfit for dinner. The star shape gives it enough personality for a dressed-up look, while the mother-of-pearl keeps it from feeling too formal.
I got the matching earrings too, and I really like how the star detail carries across the pieces. They work together without looking like I deliberately matched every single piece of jewelry.
The shell doesn't sparkle like CZ, and that's exactly what I like about it. It has a softer reflection that changes as you move, so the pendant looks slightly different in different lighting.
I was expecting a much daintier necklace, but the 17mm pendant actually has some presence. It feels like a real focal piece rather than just a tiny charm hanging from a chain.