Tax Sale Questions in Georgia - Safe or Risky?

[Ben Bakhshi]

I have attended foreclosure actions in my city before, but very recently I heard of tax sales. From the looks of it, making reasonable bid at auction can score a good deal on a home, and if the deal is "too good to be true" then lien/mortgage holders can buy the right to the deed from you within 1 year for a 20% premium. I am mainly looking for buy and hold.

So far, that looks good. I'd like to get some advice regarding my understanding of tax sales in Georgia so that I know I'm not missing any key information.

From doing my research I have painted the following picture about how they work:
Some owner with a mortgage did not pay their property taxes. So the county takes the right to auction his property at a tax sale in order to recover taxes owed.
Anyone, including the owner and lien holders (including a bank holding the mortgage) can bid at the auction.
If a third party, like myself, win at an auction price, within 1 year, the original owner OR lien/mortgage holders can legally buy the property back from me, for a 20% premium on the price paid at auction.
If no lien/mortgage holder comes to claim the deed within 1 year, the deed is transferred to the 3rd party buyer, myself, via foreclosure. I can then get title insurance and the case is closed (no one can claim ownership of the home but myself).
During the 1 year, I would be able to collect rents from the property. However, any improvements that I make in the property are non-refundable if the lien holder comes back to take the house.

What fees should I be aware of? What about after 1 year during the "foreclosure" process?

Thanks all!

Source: http://gwinnetttaxcommissioner.manatron.com/Tabs/Property/DelinquentTaxInformation/TaxLienTaxSaleGeneralInformation.aspx