The one time I raised a ticket on a corp AWS account, it was handled swiftly and competently. I'm sure it depends much on what your issue is.
Meaning if I had something I really needed help with, it was going to be a conversation for the following day.
I'm not really mad, we're just pre-release, and the number crunching to go from Developer adding 3% to cost vs. Business adding 10% to cost is too damn high. Our infra is about $10K/mo right now (pre-release), so we're talking $1000/mo for live chat and a shorter window vs. $250-300/mo we're paying right now.