The problem I had with Star Charts was that I was hoping for something to read as opposed to something that was primarily meant to be looked at. The Star Trek Maps were great. I have two copies myself) because it also had the booklet full of all sorts of information. Star Charts (which I enjoyed, don't get me wrong) was less enjoyable because a) the maps were printed in the book and the spine got in the way. With Star Trek Maps I could spread them out on the floor and just pour over them. b) the maps in Star Charts were in 2-D. No side view given. No z coordinate. They were flat. As Spock said in TWOK "His pattern indicates two-dimensional thinking." c) Voyager got too much coverage compared to the Federation/Klingon/Romulan area. Page after page of a map with a line through it and few systems. I would have preferred a more balanced approach. YMMV
I'm not too sure. I did see what appeared to be "remaindered copies" in one store, meaning it was officially no longer "in print", but this was at a time when many other stores still had full-priced copies in stock.