I've only seen four Tarkovsky films, but yes, he's a fabulous director. I've not read the book and don't know if an English translation would do it justice, so I'll take your word for it that the extremely good movie was better than its source.

Note that I didn't make that list of 6. I just thought the movie community might like to read the article. Y'all don't have to call me out with all things they skipped because I'd have put stuff like the Wizard of Oz and Ran on there (and then quickly ducked because no one gets away with saying a movie is better than Shakespear's original work).