Hal 9000 said:
I would not dream of approaching an abridged copy of Lord of the Rings, but this is Star Wars and there is a lot to get through.
When Heir to the Empire came out, I was completely taken by it. I read it several times and bought the 3 hour audiobook and listened to it several more times. At the time, I didn't notice much difference between the text and its audible abridgement.
I kept up with SW EU for several years, and started to realize a lot of it was drek around the Black Fleet Crisis series or thereabouts. I wanted more Zahn, so I bought the Thrawn Duology when it came out, but never read them.
Years ago I wanted to revisit Zahn's HTTE trilogy, so I dug up the tapes and listened to them. They were terrible. It made me wonder if the books weren't as good as I remembered them or if the abridgement was poor.
It was the abridgment. I re-read the books and found them delightful- even better than I had remembered. Better than I had been able to appreciate in 1991.
You can get the unabridged audio of HTTE anywhere fine books are sold or loaned... Dark Force Rising and The Last Command are trickier- but Audible sells them.
tl;dr- Beware the abridgement. Disappointment and underwhelment are its allies.