The phrase "plastic drum" is not quite correct. The drum washing machine is always made from steel, plastic, can be made from a tank, that is, the capacity, where is the drum.
Numerous studies of heat transfer of tanks of different materials showed that the lowest setting there is a plastic that is not surprising, since metal conducts heat much better. This parameter affects the energy consumption and electricity costs. Lower heat ensures lower energy costs, so we can say that vehicles with plastic tanks for the time you use save a lot of Finance.
The next important parameter is the noise of the tank. Again, it is not surprising that the plastic differs the least noise, because it is more ductile and has a high noise reduction. However, it should be noted that in this case the difference between metal and plastic tanks is not so great, but if you are sensitive to loud sounds, choose a machine with a plastic tank.
Unfortunately, there is a parameter that unequivocally metal tanks outperform plastic is strength. Of course, steel tanks are much stronger than plastic, because the latter do not respond well to heavy loads. During the vibration of the washing machine the counterweight is broken, and means to unseal the plastic tank of water. So the durability of this washing machine does not Shine. In addition, the guarantee offered by the manufacturer on vehicles with plastic tanks is much less than for cars with steel.
Another interesting parameter is the interaction of chemicals and their absorption in different materials. In this question the opinions of experts differ. It is impossible to clearly establish the level of reaction of the materials with the chemicals contained in washing powder or bleach, and, therefore, to assess how harmful occur harmful and toxic substances. Usually, the steel for the tanks of washing machines made from high quality, chemical resistant alloys. With plastic it's not as easy as manufacturers keep manufacturing technology in the plastic wraps, claiming that their plastic is not as toxic as steel, which is quite doubtful.
It should be noted that the average washing machine with steel tanks are more expensive than plastic that is easy to explain. Anyway, if you are going to transport the machine from place to place, want to save money and reduce the noise level, you may choose a washing machine with a plastic drum.