There maybe lots of non genuine brake pads (or any other parts) that are as good and some maybe even better but I prefer to keep my Defender as original as possible.
Many years ago I fitted non Volvo cheaper pads to my 740 petrol turbo, they cost £22, the Volvo pads were £50, they were fine until a few weeks later and I was on holiday in Scotland and coming down a long mountain pass, the brakes became hot and the cheap pads became useless and very dangerous, I drove straight to Oban Volvo dealer and bought Volvo pads and fitted them in a lay-by, I did the same mountain pass several times with Volvo pads and they were perfect, so they ended up costing me £72 a pair and could have cost me and family our lives,