Pulling delinquent tax records from the county office

I am wanting to start a direct mail campaign targeting delinquent property tax payers with low LTV's and am wondering if anyone has successfully built their own list from a basic delinquent tax roll from the county assessor's office? How informative are they, as in: can you see the last purchase date, price, how delinquent the homeowner is, etc?

I guess, I'm hesitant to spend the money on it if I'm going to need to turn around and buy my leads from a company that has more targeted leads.

Any help would be greatly appreciated!