In order to compare these two different styles of cutting metal and decide which one works better, first you need to understand how they both work. Of course, more research can be done on-line if you need to know more specifics, but just basically you can understand the similarities and differences with the following.
Oxyfuel cutting is done by controlling and speeding up the rusting process and that allows the steel to basically “break” exactly where desired and it is cut. This process is done by heating the steel up to extreme temperatures and then directing a stream of oxygen toward the hot metal and it rusts and breaks. This allows for very quick, smooth cuts, usually leaving a thin coating of rust on the edge which can then be knocked off with little effort. Plasma cutting is done differently. With plasma cutting, a thin stream of inert gas is fed between an electric arc and this forms a barrier around the weld and keeps it from oxidizing. This means you get much cleaner lines and no oxidation where the cut occurs. So you can see that although neither system actually “cuts” through the metal, the use of gas, heat, and electricity allows for speedy, clean cuts of metals. However, there are definite differences between them and plasma cutting is generally much more flexible and safer.
First of all, plasma cutting is much faster and with CNC plasma cutting and the computer running the cutter, there is even more of a difference when it comes to speed. The thinner the metal, the larger the speed difference between the two cutting methods. This is particularly noticeable when it comes to piercing speed, or making a hole in the middle of a piece of metal. With oxyfuel technology the metal has to be heated before any cutting can begin. On the other hand, the plasma cutter can pierce almost instantly.
Also, the fact that the plasma does not have that heating process means that thin metal does not warp, the torch is easy to control and handle, and the safety issues are not as huge of a factor. Obviously with oxyfuel, the cutter is working with flammable gas under high pressure as well as an open flame and if you are trying to work in an area around fumes that is a big issue. Also, insurance for a place where an oxyfuel cutter is being used is exorbitant. Plasma cutters do not require this because there is no flammable gas and there is no open flame.
Also, the CNC plasma cutting process does not produce as much waste which then has to be disposed of and dealt with and with oxyfuel, this metal is hot and comes under some federal and state regulations. CNC plasma cutters also can be used on many different types of metals than oxyfuel because the oxidation process is not necessary. That means CNC plasma can be used on even rusted, painted, or dirty metals not to mention copper, stainless steel, aluminum, etc. It can be used on alloys as well, which oxyfuel cannot because the oxidation process is necessary.
Because of all of these benefits, in most cases a CNC plasma cutter will be a better choice than oxyfuel cutting.