In my case they've been very responsive. Usually they answer after 2-3 hours.
Depending on the traffic it can take little bit longer, but they're trying to answer as soon as possible.

They're also working 24/7, so time shouldn't affect response speed at all.
And no, they're no paid support options.

Depending on the problem, you can ask your question here too. As of your question about Public IP reachability, it's hard to debug from this standpoint, so you've to wait for support.

I have seen longer response times with the DO support, however my tickets were general inquiries to billing and did not require any sort of hasty action.

I find the best way to get an answer is to first search the tutorials section as there are allot of great articles there. Next I search the questions section to see if anyone has had the same issue. If I do not find anything then I will post the question. Sometimes there is an answer right away, or may take a bit since this is a community forum and the person or persons who may replay are not available right away.

If it is an issue directly tied to the DigitalOcean platform that a community resolution is not possible I then open a ticket - As stated above my tickets have not been mission critical so I believe they have been queued in order of importance.

I have been using DO for my personal workloads and am quite happy.

Thanks for the answers.

I ended up contact DO via Facebook and they prioritised my ticket. The issue turned out to be a genuine DigitalOcean issue with a certain subnet in the SG datacenter. I'd guess DO support get a ton of support tickets each day and I'm sure a lot of them could be solved by the community or reading tutorials, it just so happens my first ticket was related to a real DO bug that couldn't be solved any other way.

I really hope DO adds some way to escalate tickets.

What if they allow me to pay $1 to escalate? It would be a simple way to raise urgent tickets while giving people with minor questions a chance to decide how urgent it really is. And if the issue turns out to be a genuine defect on DO's side they could refund it.

As it stands I don't know whether to go ahead with my migration to DO. I see the support team are pretty good but obviously swamped with support issues which have absolutely no way to be prioritised. It's the kind of thing that ends up being the downfall of these companies as the social media reviews fill up with bad reviews and they gain a bad reputation. I hope they take notice and do something.