eBay is a marketplace, not a brand. You can find almost anything for sale there....so asking if "eBay brakes" are good/bad is not the question.
I bought two sets off of eBay from BrakeMotive. One for my Accord, and one for my 1991 240sx. Each set was 4 rotors and all ceramic brake pads. Around $150 delivered per car.
My neighbor has a 2007 Accord, and money is tight. Castle Honda quoted her $1,150 for a "complete" brake job. I ordered yet another set from BrakeMotive and did that 2007 for $150 in my driveway.
Stops well, looks great, very happy.
Know that most brake rotors and pads are made in China. You may see a video of what looks to be Pittsburgh steel workers making brake rotors- but it is bull. Canada (Vancouver and Toronto) as well as California get thousands of these rotors from China. Some places will then drill and slot them in North America so they can say "Made in USA", but believe me (I've seen the factories), they are only "finished" in the USA.
Unless you go exotic, rotors are made with the same metal ratings as the next guy.
I wanted drilled and slotted for the next 5 years, and so I put them on my Accord. I just like the look and doing brakes on these cars is so easy, I went with it. You may get flamed by other Accord owners for going drilled and slotted, but you will earn respect from the neighborhood toughs and really, isn't that what life is about?
EDIT: Brake rotors are a "low tech" item. Perhaps the 10 most common brake rotor model numbers cover about 75% of all cars on the road. So high volume, low-tech, and lax environmental regulations during manufacturing equals "overseas". However, if you are autocrossing, I would go with a different brake set up.