I have dealt with large mainstream watch companies and their customer service has been anywhere from good to very luke warm. Understandably, the time and type of responses vary due to the amount of customer inquiries. BUT, the mainstream watches are abundantly more expensive and one would expect better service secondary to the cost of the item.
Customer service from Stowa, Archimede, Dornbluth, and Steinhart have been fabulous. Inquires were replied within two days and many times by the owner of the company! Most excellent.
The larger companies should take a lesson from these smaller ones.