Found that with detergent, good quality really matters and price isn't an indicator for quality.
With stain remover additives, basically everything does just fine no matter how cheap.
Here in Germany, Persil Megaperls of course work amazing.
I also have to agree that Mieles detergents in general are very good and rinse very well.
But these are expensive.
Ariel is a little cheaper but found it to be sudsy.
However, our store brands are often very good.
DMs detergents are very good but not the best - but very cheap, I like their scents and as a bonus they flush in very nicely.
Our Aldis detergent for whites actually won our consumer reports testing since it cleans very well - for a discounter price, less than half of higher end options.
Tried it myself and really liked it!