We (<20p SaaS) use Intercom with great success. It's hooked up to our support email as well, so users who prefer email can use that, while giving us a central mailbox for it. Most customers really appreciate quick, low barrier chat. We all take turns as operator (we call it Empathy Day).

As you handle support for a while, certain recurring topics appear. We identify these and either use canned responses (macros), or (preferably) improve our product to prevent these questions in the first place. We also have a bot for some basic things like pointing at the docs for certain topics.

We sometimes are asked to jump on a call, but only do that for highly technical support requests and enterprise customers. Since we have customers worldwide and a globally distributed team, synchronous communication is tricky anyway.