The ones I saw from a quick search were nice looking but pretty pricey. Basic Gold rings were going for the same price as some of the fancier designs so I think that would be more of a design / aesthetic choice.
Titanium / Tungsten / Silver are for people who want an inexpensive ring.
Funny because titanium is actually a very cheap material. I got a 1" cube of it for about $30. I assume almost all of the price is labor for working with it rather than the cost of the metal itself.
