I went to the Grad School as part of meeting the education hours before taking the test. IMO - The content of the school is more management and not a great preperation for the test.
I studied the ABA guide on my own and I wish I had used the online portion as well - keeping me on track with a study schedule, etc.
Also, as others said, preparing for the way the questions are worded & practicing " stepping out of your bank situation " and applying principals is great.
A question might give a situation and ask what should you do first - and one of the answers might be "Tell the Pres"
If you are from a smaller institution with an active Pres that wants to be kept informed of every situation / problem & hates to be suppriesed . . . This might be your real-life correct answer but not the correct answer for the test.
My opinions are just that, and might be worth what you paid for them.