Tax Deed sales vs Tax Lien sales, a rundown anyone?

I am a newbie investor in Chicago. The Cook County annual tax sale is in progress and I would like to look on only this year. Can anyone give the basics as above, and also anyone made any money from buying these?

In a Tax Deed sale, the county sells full ownership and possession rights to the property. In a tax lien sale, the county is selling their right to the tax lien only, the buyer pays the delinquent taxes in exchange for a first lien position on the tiltle, ranking ahead of other mortgages and private liens, second only to state tax liens. The buyer receives a tax lien certificate, a penalty interest rate until the tax debt is fully repaid, and a right of foreclosure to take title if it isn't paid.
Clearly you get a chance at a lucrative investment for a fraction of the cost of the Tax Deed option.
I thnk the annual sale in progress you refer to will be for foreclosed propertyor Tax Deed. You need to check out the terms at the Sale, conducted by a private company in Cook County case. Most states have a 20 to 25% deposit requirement, with the balance of the winning bid quickly (24 hrs to 10 days). My experience is that many properties revert back to the lender and many scheduled for sale get postponed or cancelled. There is also stiff competition from commercial company investors. You need to be up to date with the size of the other liens and judgments and/or any bankruptcy proceedings, and the redemption period allowed by the state code. Have heard of some good deals, but it's not an easy choice for the new investor.