Do you mean that the Birkhoff and MacLane book was used for second year math students? Were students taught about categories in their second year? ( sorry for getting off topic, just curious )

Re: Is Spivak's "Calculus" rigourous and comprehensive enough for an analysis course?

Maclane & Birkhoff "Algebra" is the category-theoretic experimental text. Birkhoff & Maclane "A Survey of Modern Algebra" is one of the mainstays of introductory algebra texts.

Re: Is Spivak's "Calculus" rigourous and comprehensive enough for an analysis course?

Thanks for clearing that up, I'm not too familiar with their other algebra book, so when I hear "Mac lane" I just think of the bigger Algebra book ( when do you think the bigger "Algebra" book would fit into a standard "pure" mathematics curriculum? )

Maclane & Birkhoff is a bit higher level than Birkhoff & Maclane owing to the intention to introduce modern levels of abstraction such as categories and modules at an earlier stage than would have been customary in the late 60's. As they indicate in the Preface to the First Edition:

It's my impression that the book was not widely adopted, but I recall at the time the idea seemed cool.