Actually had my RD Sympathie bi-retrograde moonphase chronograph serviced and regulated recently by a master watchmaker friend as he did it in 3 weeks instead of 4 months if I sent it back to RD in Switzerland. It also cost considerably less as well but maybe he gave me the "golf buddy" discount 😉😁.
Also recently picked up my Nautilus 5980/1A-014 black dial which was serviced at Patek Place Vendôme but with most any Patek, I would only send the watch to them.
Currently have a Zeitwerk getting some spa treatment as well since it suffered a cracked crystal and dent in thelugs due to a mishap during a photo session with Jesse J 🤦♂️😢
It really just depends on the watch and manufacturer 🤷♂️