To be honest, most chems perform well. The secret is knowing which fibre/construction/soiling responds to which chems.
In general terms, detergent technology is very advanced and, IMO, because of evermore restrictive H&S regulations, tend to be quite narrowly focused in their best use.
Relatively speaking, detergent free technology is in it's infancy. The ingredients are typically simpler and greener and , as highlighted by Derek because of the typical degree of agitation required, tend to work in a wider spectrum of soil/fibre types. Although detergents can often perform well with less or even no agitation, even the less agressive wool suitable products can perform on heavier soiling levels if agitation is used at a similar level to the detergent free products.
As much as it is about chemistry, it's also about physics, so always have in mind the C.H.A.T/T.A.C.T. cleaning pie.
Safe and happy cleaning
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Ken