Hey Spike,
Titanium's gotten much less rare, following the fall of the Soviet Union. The Russian titanium spigot is wide open. Titanium is turning up in lots of places: golf clubs, wedding rings, production motorcycle exhausts, bicycles, and trem blocks/barrel saddles. There used to be only a couple Ti bicycle makers. Now there are so many, there are even generic Ti bikes.
Titanium is a bear to machine. It's gummy, generates a lot of heat, and wears out cutters. Casting isn't too bad for non structural titanium. Oxygen is bad for strength in molten titanium, but, for golf clubs and trem blocks strength isn't much of an issue.
Ti is stronger than aluminum and less dense than steel. It isn't as strong as higher strength steels, nickel alloys (like Inconel), and some more exotic alloys. In aerospace, we start with aluminum. If we need more strength we go to titanium. If that doesn't work, it turns to steel. That's for parts with concentrated loadings. When the loads are distributed, it's aluminum, then carbon fiber... then maybe metal/carbon fiber hybrids like GLARE or Ti/GR.