Titanium has a lot of unique working characteristics, depending on the grade used. The most common grade used in knifemaking is 6AL4V. This grade of titanium is tough on tooling. It drills best a slow speeds with lube, likewise it grinds best with belts running at slower speeds.
The best word I can use to describe it is "tough"...it's not hard, in fact about the best you can do for hardness is approx Rc 48 (depending on the grade). There is no "heat treating" with Ti, at least not in the sense that most knifemakers would think of. Several years ago there was a big buzz about using Ti for blades and having it "Nitride" coated, but that faded fairly quickly one everyone realized that after the first sharpening, the nitride coating was gone, and the edge was back to straight titaninum.
Knifemakers value it for it's light weight, and the ability to color it via anodizing. During the last decade, titanium has pretty much become the standard for folding knife liners.
A few years ago, ABS Mastersmith Tom Ferry came up with a process of laminating titanium into a damascus like product called Timascus (TM)...he, along with a couple of others that he works with hold the patent for that process and material.
One of the biggest dangers has already been mentioned....the white hot sparks that it gives off when grinding. I've had the unfortunate experience of having a pile of Ti shavings ignite...and water will not put out the fire!
Another hazard that needs to be addressed is that Ti produces toxic fumes when ground....although we don't hear much about it, a number of folks I know have had "Titanium poisoning". A GOOD respirator with harmful vapor filters, and lots of fresh air are a good idea when grinding it.
Once you learn and understand the material, it's not all that difficult to work with. The prices on it vary widely, so if your looking at purchasing titanium, it's worth your effort to look around and seek different sources. Many time I have found different sources for the same grade, with one source being half the price of the other.