I've only done viewings with them, as a potential buyer, so far. They were fine, same as all the others.
Granted, I've never actually been into an estate agent that "benefits" from a local office, they seem to be prone to ignoring emails and messages as you'd expect from unnecessary middle men (see travel agents) in fact I'd say one without an office might be a bit more inclined to take non-face-to-face contact a bit more seriously.
Their time is coming, disruptive technology will tear the house down sooner or later, when their expedia or uber or airbnb arrives. Sorry, I appear to have gone off on one