After reading about your experiences with the faster eating perk bug I decided not to use it. So far only very minimal musical chairs where customers stand to consume their drinks. Mostly they sit back down and manage to complete their meal but occasionally, if a waiter is serving the table at the same time as the 'drinking sim' goes to retake their seat the waiter and the 'drinking sim' resets but not any other sims who are already sitting and eating. Interestingly this hasn't happened while visiting an NPC lot and I played that side of things for about 7 hours today.
*All the hired staff have been working failry well, a few needed a bit of prodding but seeing as that is part of the game play it is to be expected.