I suppose it isn't entirely paradoxical, but I disliked the dragon book, even though I rather liked Hopcroft/Motwani/Ullman's (theoretical, non-compiler book) Automata Theory, Languages, and Computation. (Turing award winner) Ullman giveth and taketh away.

Purple dragon (Aho/Lam/Sethi/Ullman) is probably better than red (or green) dragon though, as it adds some interesting topics.

In an undergrad course, I'd probably prefer a simple book that uses recursive descent.

Yes, my undergrad school was dominated by some compiler researchers. We didn't cover it all, by any means, but we built lots of lexers, parsers, and interpreters. There was an elective that went through the rest of the book. Crafting Interpreters would have been a better textbook, but it wasn't available at the time.