I've been skimming through Falnagan's "Ruby Programming Language" to see if I should spend the time to learn Ruby. Their presentation is similar to K&R, with the exception of nonexistent practice problems, which I think is what made K&R so great.

Now I'm tempted to pick up the new Pickaxe book, but should I? In what ways does the Pickaxe do well while Falnagan's does not?

The main draw of the Pickaxe book is that it's the only book out there that includes the complete reference for Ruby and all the new features introduced in Ruby 1.9. While the book isn't a straight walk-through of the language, and lacks some explanation with some of the major language niceties, I'd say this book is an invaluable addition to any Rubyist.

I'd have to agree. While it's not a great walkthrough style programming book, it is certainly a very useful reference.