What is the deciding factor as to which pre-ferment to use, poolish, biga or pate fermente, or is it personal preference?
There are slight flavor differences among them that some people claim to detect....I'm not one of them, although maybe I could if they were placed side-by-side. But who does that?
Poolish also supposedly increases the extensibility of the dough and biga the strength.
My bet is that the vast majority of the people can't tell the difference, even if they say they can. Since any preferment (or a day or two rest in the refrigerator) greatly improves the flavor of bread, I usually go with the easiest to mix, which is poolish.
In the discussion you'll find a link to an article written by Didier Rosada.
Indeed flavour differences are subtle but handling is strongly effected by which type of pre-ferment you use and how much of it you use. The more you use the greater the effect. A biga can be used at 100% and is suited to high rising and enriched breads or breads made with a lot of water (ciabatta). Poolish is more limited but is well suited to baguettes since they don't require much height and need to be extended into a long shape.