I would say that instead of how fast a first response is offered. We can take how many support tickets are solved fastest and how good they offer support. Big providers does not provide easy support like email support.
You have to go through their departments and explain everytime to someone your issue. Where as small companies will have direct support for customers. Single point of contact.
The best part you will get direct help.
I do not know what other providers do, but we take care of our customers, there are lot of cases when we have provided support to customers via teamviewer as well.
We even maintain a dedicated youtube channel to help complete newbies to learn to use our hosting. May be not everyone can do the same. I would say, instead of how long it take for your host to respond, its better to see how many times you are asking for support.
Is their server go down frequently? Their servers are unstable?
If these are the reasons for support tickets, then you should probabily look for a new host.
Yes, hosting companies get email notifcation by support ticketing system, whenever they got a ticket raised by customer. Sometimes, they may ignore it due to level of priority of ticket or overloaded by tickets.
Less than 6 hours response is good in most cases (general) . In case of server is down, then 30 mins or less is good. These are just approximate times, I am providing here. Each company have its own SLA and Terms. Customer should read and understand things prior to purchase.
Note: My personal opinions. Some people may not agree or agree. This is what I think is good, when it comes to support for web hosting.