Actually,
my experience has been that UK brands, like all European products clean considerably better than do the American products.
We just plain have more phosphates, considerably higher enzyme dosages and more effective bleaches as well as protective agents.
Nothing I have ever tried cleans as well as SOMAT or MIELE (I strongly suspect they are the same thing). The Lidl and Aldi and Schlecker and Rossmann and DM and Tengleman house brands all work fine on Universal 55° (the special program my Miele uses which raises the water temperature in a special curve to match the enzymes needs perfectly). On a normal wash, nothing clens everything as well as SOMAT or MIELE.
I prefer the tabs for the simple reason that the powders make my nose burn. And powder for the pre-rinse hasn't been needed for decades.
American dishwashers, given a decent detergent - like Somat 7in1 clean just as well as do ours. It isn't the machines, it is the castrated detergents.
Same with the laundry products.