I've been updating my blog and discovered this in the drafts folder. It's part 3 of a series I did a few years ago about "Indie App PR", based on what I learned in promoting and supporting Remembary: The Connected Diary. Here's Part 1, How to Handle an App Disaster and Part 2, Keeping On Top of User Feedback.
It's natural to have a bad reaction to negative comments or criticism, especially in a crisis situation where you're already feeling stressed and defensive. It's almost always a bad idea to shoot knee-jerk bile back at people - no matter how much they may deserve it. If they have valid complaints, then they'll be upset by your comments; if they're trolls, then harsh feedback will only encourage them. No matter who they are, remember that they can write anything they want in their reviews on your App Store page. They also likely have Twitter accounts and networks of friends.
Writing on-message, well toned responses to colourful criticism is some of the most difficult writing I've done. Here are some pointers:
It's amazing how much a positive response can completely change the tone of a commenter or critic. Look at this set of comments and replies to the AppAdvice article to see how I managed to turn things around (with only a bit of snark). The initial post from "Brett" is mostly harsh criticism, but by the third reply he has admitted that he has ditched MaxJournal for Remembary.