brand choice is relative as well as the word best. if you refer to athletes, they'd go for their sponsor. why wouldn't schurter use fox, dvo, etc? because he's sponsored by SRAM - simple as that.
in the end, you'll be the one to set your requirements. personally, i'd go for RS since spares and kits can be easily purchased locally and this brand consistently releases tech docs. availability and after sales support is among the top of my requirements when purchasing stuff.