AstroSynthesis v2.X was an excellent three dimensional mapping program, but v3.0 is even better. It does everything it says on the tin.
Everything in the new version of AstroSynthesis seems improved over 2.X. Switching from interstellar views to intra-system views is the first obvious difference, and makes use of the program feel much more fluid. The addition of a calendar is also a wonderful feature of the new release. The program is a little bit unconventional in navigation, but it is very easy to learn, with solid documentation. AS 3.0 handles very large maps more smoothly than in past releases, so if you have more than a few star systems you'd like to map, this is an excellent way to do so.
I wish that there was a "control-Z" undo function, and I wish that I could set stars in a close multiple system orbiting the combined center of gravity. It is possible to make unintended changes, and then be stuck with them. My solution has been to save often and revert, but that is less than ideal. For multiple systems, there are also work-arounds.
The community of users has supported the program with some handy scripts in the past, with plug-ins to support Traveler and GURPS, as well as some universally useful tools. Support from the publisher is solid. The forum is sparsely populated, but checked by the publisher frequently.