Recommend me your best clothes washing detergent?

Powder detergents are generally better than liquids, because liquid detergents are more limited in what ingredients they can contain to avoid interactions in the bottle, for example they can't put oxygen bleach, or bleach activator (TAED) in liquids because it would break down the enzymes.

The residue left coating the inside of the machine from liquid detergents also tends to trap moisture, providing bacteria a medium to grow in, so the machine is more likely to smell bad.

Oxygen bleach not only is an effective stain remover, it kills bacteria and viruses both in your laundry and in the machine. Oxygen bleach + TAED makes a highly effective biocide (peracetic acid).

Incidentally bacterial biofilm build up in a washing machine can cause the aluminium spider to corrode and fail prematurely. Leaving the door + draw open between washes to reduce the moisture level will help to combat both mould and bacteria, as will an occasional 60°C+ hot wash.

Still liquid detergent is more popular than powder, and the manufactures charge more for it, and can sell you extra additives to make up for its deficiencies, like oxygen bleach based stain remover, laundry sanitiser, and scent beads, so it is more profitable for them.


(edited)