Kaplan's dentEssentials: great if you like organized charts. Not too wordy, lacks detailed explanations. Good for dental anatomy and occlusion section. Organized by systems, difficult to search for particular subjects.
2009-2010 dental decks: detailed explanations, based off old exam questions. Good explanations and great review of dense material. Lots of errors (check dental deck website for posted corrections). Lacks overall organization and visual aids.
1st Aid book: good organization and explanations. Great visual aids, good for anatomy. Lacks details (add material from dental decks while reading and this can be helpful.) Some errors, mostly spelling. Great for "quick reference" but still will need textbooks and lecture information to achieve a good score.
Crack the NBDE: poor source for "questions." Good to give you an idea of what the exam will be like in terms of computer program system. Lacks explanations of questions.
Kaplan Q-bank: good explanations of questions, question are too easy however. Progress report shows you strengths and weaknesses. Repeats a lot of questions, so really there is only about 400 questions.
ASDA released exams: released exam questions from NBDE part 1. Newer questions are repeats of the old exams however. Questions seem "easier" than the recent NBDE part 1 examinations. No explanations to questions.
*I would recommend 2009-2010 dental decks if I had to chose one of the above only.