[weby]

Overall I have enjoyed most of the Gurps Traveller line(The rules just kind of make mostly sense mostly, specially when compared to something like classic traveller)

Though the books are mustly useful if you do indeed run Traveller or something close to it also of note is that the actual rules bits are 3rd edition for most of the books.

Over the years I have found use for the books in other uses besides travller too as I have never actually run a GURPS traveller game(too many other genres to run to run everything)

Some notes where I have found them nice:
-Ground forces: The modular grav vehicle rules: though they are now bit obsolete because they are third edition so the end result needs to get 4th edition stats.
-Star Mercs: The simplified ground combat system is still used today by me.
-Starports: There is a lot of "how starports work" and "what all things are likely found on starports" material that I have used a lot in other scifi games.
-Planetary surveys: I have used several of them as places in other scifi campaigns.

As for running Traveller one day: Interstellar wars is the book to get, it is in many ways the "4th edition traveller core book" as it contains things like the 4th edition version of the modular ship building system found in the core book.