EOCS - Schweser vs. CFAI

Which one do you find harder and which one do you think is more useful for the exam; Schweser EOCQs or CFAI EOCQs? I find CFAI EOCQs harder than Schweser EOCQs but not sure what does it mean. Should we be more focused on mastering the concepts in CFAI EOCQs or Schweser EOCQs?

http://www.analystforum.com/phorums/read.php?13,1148590

Thanks green360. This is exactly what I was looking for.