I'm studying for the MCAD and using Kalani's books.  I find them helpful.  Also, contact a test center like New Horizons and ask them for some keys to msmeasureup.com (they give them away usually).  There you can take practice tests in study/cert/adaptive modes.

As far as taking classes from a test center, I personally do not recommend it.  They are very expensive and I don't feel they saved me any time or studying.

The salary issue really does depend on the employer.  I was able to negotiate an increase in salary upon completion of my MCAD based on the statistics in the "Profit and Loss" article at mcpmag.com.

Hope that helps, and good luck!