Haven't had a warranty issue, doubt if I will, but based on some customer service interaction recently when I purchased my new McDermott, I'll give a thumbs up to McDermott - excellent! 50th Anniversary is one darn fine cue!
With one warranty issue a few years ago, but just customer service in general, big thumbs up to Schmelke. I have several, because Schmelke seemed a good option for filling out my rack when I finally got my table up and running years ago, and really enjoyed him visiting with me personally about my needs/options.
With a custom maker and a minor issue with a cue that had it needing to be returned for a minor and quick "fix" - Pat Diveney, super guy.