While I’ve only dealt with Discover support for a couple of minor issues, it definitely left a positive impression. There was no automated system I had to fight against and a native English speaker answered right away. They were also knowledgeable and not just reading from a script. Definitely among the better customer service experiences I have had.
I’ve been using Runbox for a couple of years and agree the web interface is lacking. There were also multiple significant server outages last year, but it has been much more reliable this year. As long as you don’t use the webmail often, Runbox is a good affordable email provider and is great for families due to the low cost of sub accounts (additional users).