I got mine back from service about 2 weeks ago or so. They had replaced the keyboard (per Apple's instructions) and claimed the issue was solved and that Apple had been informed that this could also be a firmware issue. Well, when I got it back, despite their claim, it was not fixed. I had enough and left it back.
I was contacted by Apple a few hours later and they wanted the machine for internal testing and offered to replace it with a new one, however I don't know if they ever got it, since I had already left it back to my retailer. I did give them the contact details.
Due to mistake by the retailer, they had sent the machine I had returned back to service and about a week later I was contacted by the retailer to pick up the laptop from service (who had done nothing, claiming a firmware issue). I advised them the laptop no longer belongs to me... but it was interesting to see that on the second time around they no longer mindlessly swapped components in an attempt to fix it and simply stated firmware problem.
In general, it has taken Apple a long time to fix it or officially recognize the problem. It seems unfair to leave the customers waiting for confirmation if this is hardware or software problem as many are running out of time to return their possibly faulty hardware to the retailer (in case they don't want to enter the service cycle). Other thing that didn't really impress me was the fact that only the service didn't properly test the unit if their "fix" was working, it was also covered in fatty oily fingerprints when I got it back. Must be terrible effort to wipe the display before sending it back to the client....