Specifically, support and billing.
We've used Gold support for a while, and our experience wasn't great. Pretty much the same as the OP described with Silver. Perhaps response times were slightly faster I imagine, but I would be surprised if quality was any different.
Regarding billing, we've been going through some kafkaesque cycle there trying to set invoiced billing. I've filled a form on their invoiced billing page, a sales contact talked to me on the phone and I explained everything. She then sent an email asking me to fill another form, which I did, and then got contacted by another billing team who basically sent me to the original page. I explained the situation and they just didn't really seem to care or understand what's going on. They then tried to arrange a call, but missed two schedules that I've set, called the wrong number, wrong country code... Not sure where this phone call would lead. Absolutely mind boggling experience there. Teams don't talk to each other. They send the customer around running in circles. It's amazing that it's happening with one of the most sophisticated companies in the world in the 21st century.