I bought one of those titanium kitchen knives from Boker(www.bokerusa.com). I tried to live with this thing for a few months; I declare this experiment to be complete, and I give thumbs down to this expensive toy.
This worthless 7 inch slicing knife (I used it as an all purpose kitchen prep knife) I bought for $50 plus S/H on the company website on closeout. It is listed by the company and other websites at $175, but I am considering it as a $50 knife; my opinion would be harsher if I decided to use the $175 price tag; the only task it did reliably was opening bags of chips and packages of cookies. I should also note that I got the original version, not the newer ceramic-titanium blend. The blade is thin and extremely lightweight (this both good and bad, depending on what you are doing); the blade will flex if you press it on the cutting board, sort of like a fish fillet knife.
When I first got this knife, straight out of the box it did not cut very well. After several weeks of trying to get this thing to work as an everyday, high quality kitchen knife, I was about to consign this thing to one of my many knife rolls never to be seen again except by the occasional guest just to show off my knife collection. I took it to the knife guy at the farmer's market, and he put a real good edge on the blade, and I now am happy to use it as one of my everyday knives.
I was reluctant to have this knife sharpened despite its lack of cutting quality. I read several blogs that said these titanium knives would clog up the cutting wheels on a Chef's Choice electric knife sharpener, so I took it to the knife guy at the farmer's market. Boy, was this a good decision. Not only would this knife have destroyed the Chef's Choice, it would also have destroyed the edge of the knife.
The origin of titanium knives in general I think started with dive knives used by Navy Seals. They needed a good non-ferrous knife they could use when dealing with magnetic mines. There are several non-ferrous metals that make decent (if expensive) knives (cobalt, tungsten, titanium). Since several DoD contractors had experience dealing with titanium, a knife with this metal was a logical, easy step. American manufacturers picked up on the PR value of this, and now make and advertise kitchen knives made with this metal, without mentioning its origin, raison d'etre, or weaknesses.
Permit me to be a science wonk for a moment. The knife guy said that my knife had a steel core with a titanium outer coating, consistent with the $50 price tag. A 100% titanium blade would cost close to five bills. Many companies are making coated knives claiming that these coatings will extend the life of blade sharpness; however, I do not agree with this statement, opinions of various famous, respected knife manufacturers not withstanding. The initial purchase of a blade is done with the point; the trailing edge has little, if anything, to do with the cutting or wear of the v-shaped cutting edge. This misconception started, I think, with the samurai swords (very famous, very sought after, very expensive if you can get your hands on a genuine one) during the Sengoku era in Japan. These blades sort of seem like (but are very different from) a simple, coated blade. These Japanese blades had a softer inner core and a super-tough but klunky coating. A super-tough coating would indeed cut through armor, but would easily shatter; so the inner core of the blade is a softer steel allowing the blade to bend rather than break. I read several blogs (and you know how reliable these are) saying that there was at one point a tungsten blade, and some modern knife makers, that make coated blades on one side. If it is coated (tungsten or titanium) only one side, AND the blade is sharpened only on one (the softer, steel) side, the steel wears down, but the cutting edge is retained by the harder tungsten or titanium side. Result: out of the box, the cutting edge is less keen, but after months of heavy usage, the edge is still pretty similar, whereas a high-carbon steel blade would require a sharpening. So, unless you are punching through refrigerator doors or car trunks on a daily basis, I see little advantage in buying a kitchen knife coated with titanium.
There are a couple of obscure advantages to titanium. In many cases in life, knives are not going to get proper care and cleaning (here, I am thinking of camping, hunting, fishing). Contrary to what many people think, even high quality high-carbon, stainless 440C steel of expensive kitchen knives will rust if you do not properly care for them. Titanium, even if you just wipe it off on your fishing vest or just swish it in a stream and toss it into your pack, will NEVER rust and always be pristinely clean. If you drop your knife on a hard, ceramic floor or foolishly apply torque to your expensive kitchen knife with stars or pitchforks on the blade, the blade has a good chance of snapping in half or having the cutting edge shatter; with titanium, these will never happen. A titanium coated knife, even if it has softer, high carbon stainless 440C steel underneath, will be almost impossible to break.
Based on titanium’s metallurgy, I suspect that the lifespan of the cutting edge of a pure, 100% titanium blade can be measured in years, if not decades in the typical home setting. When it needs sharpening, 100% titanium must be entirely re-ground afresh, and not just have the cutting edge re-honed like that of typical high-carbon stainless steel kitchen knives.