I am both a tax deed investor, and a tax deed litigation attorney. Tax deeds can be great, but they are not easy. You're stuck with the property for a full year, and can't do anything with it during that time. After the year expires, you must bar/foreclose the right of redemption of all interested parties, not just the tax debtor. If the tax debtor is dead (and depending on whether he died before or after the tax debt was incurred) things can be more problematic. Once you've barred the right of redemption, you must still file a quiet title action, since the barment process is not reflected in the deed records, except via a self-serving affidavit. The quiet title process is also complicated in that most title insurance companies want a full "against all the world" quiet title, rather than the slightly simply "conventional" quiet title.
Buying in too cheaply can be risky, in that if you incur attorney fees to bar the right of redemption, and an interested party comes forward to redeem, then even with the 20% (or more) redemption period, you may be upside down.
There are also property-specific risks, like HOA dues and limitations. If you end up bidding on "common area" in an HOA, then it may be that literally every other homeowner in the community is an interested party with a right of redemption that must be barred. Further, you must pay HOA dues and assessments while your redemption period runs.
I also hate Fulton County for tax sales, because of their policy of re-selling their tax liens to third parties, who then conduct the tax deed sale, because if a tax appeal is pending of a tax lien that has been sold, often the third party ends up selling a tax deed based on a void tax levy, and untangling that results, best case scenario, in only a refund of your money, but no reimbursement of your time and costs in getting that refund, which can be extensive.
Long story short, they're great investments if you are savvy (or have a savvy team of helpers), but there are landmines along the way for sure.
