I've been using Step by Step in Esperanto by Montagu Butler.

I like it so far. I'm only on lesson 48 -- barely started really.

So take what I say with a grain of salt since I've only read a small fraction of the book so far.

The book has lots of small lessons,that take maybe 10 to 15 minutes each -- the biggest plus in my opinion. Peeking to the back of the book, there are 1,198 lessons (the book itself is less than 300 pages though, that last lesson is on page 269), and it has lots of repetition of the words it introduces to help build up vocabulary.

The main things I don't like about the book are that there is no glossary to look up words and the print in the book is small and hard on the eyes.

I've just completed the flashcard sets for "Teach Yourself Esperanto" (1987 ed) up on quizlet.com, also did the word lists for "Gerda Malaperis". Best to visit the esperanto group and scroll down:

http://quizlet.com/group/1200/

Enjoy
jaffa