The so called "miracle" is not living up to its name... Which is why sites like GardenWeb are doing well. There was never any good place to get information about gardening materials and products before. I have a variety of zoysia called Shadow Turf. I plugged it back in May and it sat seemingly dormant until late July. Then it came in like gangbusters. It is every bit as aggressive as bermuda, so it needs to be contained. Also it is expensive...but it spreads. Shadow Turf was named because it grows so well in the shade.

Taken last night, just for you. http://img26.imageshack.us/img26/1174/bermudafescuecomparison.jpg That brown grass on the top is bermuda as of yesterday. Not a green blade in sight. The grass adjoining that space is fescue and look how beautiful and dark green that is. Bermuda does not hold a candle to that color which is why fescue is used so much in professionally designed landscapes. Bermuda doesn't just "show the winter season" as you put it. It's brown in fall, winter and spring. And if it's dry summer, it's brown in summer. Heck, you're in Athens, you know it snowed here this week. Bermuda will not be green for some time to come. The only green bermuda you see is the lawns that have been taken over by weeds, which is most of them that haven't used pre-ermegent in the fall. Believe me, you don't want to be stuck with a brown, weed infested, ugly lawn while everyone else has a gorgeous lush fescue or thermal bluegrass lawn. You're in Athens,GA I'm sure you've heard of the term "Gnat line" being used. Well warm season grass is for areas "below the gnat line".

As to your original question: Many have had satisfying results from overseeding in the Fall. Success primarily depends on sunlight reaching the seed and proper irrigation for the 3-4 weeks that it takes for KBG to germinate. As would be expected, seed will take best in bare and thinner areas of the lawn. (keep in mind the need to match growth rates, color, and blade width between the new seed and the existing turf). I, personally have had very good results from overseeding. So, in my opinion overseeding works and is worth it, but results will vary. What puzzles me about your sittuation is what condition your condition is? It sounds like your major issue is loss due to disease. People particularly in the East are reporting increased brown patch issues this year with their TTTF lawns. To avoid brown patch damage you need to be proactive with preventative fungacides and reactive with curative fungacides. Brown patch usually (but not always) does permanent damage to the turf and as I said, TF doesn't possess the ability to spread and fill in in the Fall. So I'm a bit puzzled by what you are reporting. Anyway, the best thing to do about reoccuring disease problems is a preventative and currative fungicide regiment. Weak grass is more susceptable to disease, so you should see if there are any weak links. Get a soil test and see if you are low on any nutrients. The greatest improvement in turf will come from proper mowing, irrigation and fertilization.Make sure your turf is getting proper irrigation. Too much irrigation can be worse than too little, Do a screw-driver test to see if moisture is penetrating (poor water penetration (hydrophobia) can often be repaired by shampooing) If your soil is not holding moisture--add organic matter. What types of fertilizer are you using and what schedule? How often are you mowing and what height?

Can you give us some more details on where you are? Zone 6 only tells us how cold it gets in the winter. I'm technically in zone 6, but I say zone 5 because people assume too much about zones. My lawn is mostly native grasses, with a few introduced grasses and some clover. I don't fertilize and I water three times a year (most of my neighbors probably water more than 100 times a year).