Ebay is certainly hit and miss at the best of times that is for sure, though I have had great success buying tomato seeds from there and have done so for about 10 years or so with very little problems. However, I did not have the same luck with buying my pepper seeds last year with all 3 types not being what I had thought they were going to be. I did buy some carn plants about 2 years ago and grew several plants which did pretty well until we went away on vacation and they were drowned by the person watching the house for us.
Buying from the Asian sellers can be risky but sometimes if you go the bidding route can buy alot of seeds for .25 to.30 cents for packs of seeds, so for very little money it is sometimes worth the risk ( to me anyways). If your looking for better odds stick to the European and North American sellers it would certainly give the buyer a better chance at buying truer seeds.