This discussion/comparison, as to which is better and the correct definition of these terms, comes up frequently in the knife world. Personally I do not believe there is a correct answer, just a lot of differing opinions. However, I believe expressing some thoughts on the subject is a useful exercise and will help people better understand the discussions and debates that arise.
Definitions
First I would like to address the definitions. A custom knife is often described as one made entirely by hand by a single knife maker, the design and materials unique to the specific knife. Often the definition is expanded to allow multiple variations of the same knife design with customization of the materials used, such as different blade steels, bolster and/or handle materials or other aesthetic variations. Further, the same knife design and materials can be repeated in multiple knives but still considered custom as each knife is made by hand by the same individual knifemaker.
Midtech is usually described as not entirely hand made. The concept with midtech is that you have a machine and/or less skilled laborers make the parts requiring less precision, while the knifemaker fits and finalizes the parts requiring more precision and/or a higher level of skill.
Midtech usually incorporates serial production in whole or in batches with machine made parts. The knife may be made by a single knife maker using specialized equipment in his own shop, or parts like the blades or frames may be farmed out for production with the use of CNC, water jet or laser equipment. The extent to which machining is part of the custom vs. midtech debate. Some people feel that using a mill is fine but using CNC equipment changes things while others feel that using CNC is simply a new way of doing things.
By incorporating the statement “a custom knife is often described as one made entirely by hand by a single knife maker” one can open an entirely different can of worms. A discussion of handmade can go to an entirely different level and will not be addressed in much detail because it can come down to forging the steel, making the screws, using materials made by others and that is an entirely different discussion.
The Comparison
There can be no real comparison of midtech vs. custom as the skill of the individual knifemaker as well as that of the parts produced by other than the hands of the knifemaker are what truly make the difference as to quality. On a broader scale however using mass-produced pieces where it doesn’t matter as much and hand-fitted pieces where it does, midtech can offer quality that is virtually the same as a full custom knife. Very few knives are truly full customs pieces. Even the highest end custom makers often use a few off the shelf parts, even if it is just a few screws.
Why even bother with a comparison, there are a couple reasons, one is cost. Midtech knives are less expensive to make and usually sell for 1/3 to ½ of what a comparable custom would sell for. The quality may be just as good as a comparable custom. Another reason is availability. By their nature midtech are produced in greater quantities than customs so they are easier to acquire. You may very much desire to have a knife from a specific maker and it is easier and less costly to acquire a midtech produced by Todd Begg, Michael Burch, Rick Hinderer or any other number of knifemakers.
The reasons listed so far, for comparison, tilt the scales towards midtech as being the better choice. Lets look at other reasons for a comparison that, tilt the scales in the other direction. One such reason is to have and own a unique knife made by an individual knifemaker, there is a pride of ownership that goes along with the aesthetic and practical qualities of the knife. An appropriate analogy would be owning a painting (custom) by a master vs. a lithograph (midtech) or a print (production). The pride of ownership and value remains with the custom.
Other reasons to own a custom may be that there is a personal relationship with the maker or there may have even been design input or specific requests for materials by the owner that would make the knife special to the individual.
Conclusion
Midtech can be an excellent way to get a good knife from a maker, whose knife(s) you desire to own, at a reasonable price. Acquiring a custom knife offers the opportunity to own something special and unique.