Best TAC Services from Equipment Vendors

Thought about it but so far I believe companies from China provide better and fast TAC responses to their customers than the likes of Cisco and perhaps that’s why some companies(where there are no restrictions)prefer them for critical services. For a short period in TAC call you can have over 10 R&D engineers and solutions provided in a matter of hours even if it involves software changes.. while these other companies even before you get in a call with a TAC engineer it’s hours and when they join you hear something like “my shift ended 15 minutes ago, hold let me look for another engineer”. WHY? Thoughts