Rightly or wrongly I consider
Bondhus the benchmark for such things; I have a set of metric ball end Allen keys which see regular use, have worn well and weren't eye-wateringly expensive.
That said they're a different format to many which may or may not be to your taste.
While I've often dangled the carrot of a set in front of myself I've never quite been convinced by their functionality (not sure about having all that mass hanging off the top during fine work / around easily-damaged stuff) or value in terms of cost, functionality and storage space compared to a humble set of
Allen keys for 30-40% of the price.
That said the majority of my work is on more delicate toys; they might feel more appropriate on bikes, cars and generally larger stuff.