Yes it sounds like you have the problem too but it also sounds like this is just the way the Hyundai works. It's perfect on the Iiyama I have seen and nearly perfect on the Viewsonic VX912B. Such is life.
If we wanted the perfect TFT then we'd be waiting years for it. The point of this thread for me was that other L90D+ owners had said there was no banding on theirs and there was on mine, so all I'm trying to establish is whether I had a faulty or substandard unit.
I'm happy to have fast 8ms response, it's just a shame that the technology at the moment means it's like running 16-bit desktop colour, back in the old days of the Nvidia TNT2.