Are aftermarket parts okay for a Range Rover or should I stick to original?

A small argument started in my house last night and I would like to settle it with some outside opinions. My Range Rover Sport is seven years old, and the front brake pads and a few other bits need changing soon. The workshop I use gave me two prices, one for original parts and one for what they called aftermarket ones, and the difference was big, almost forty percent. My wife says take the cheaper one, because the car is not new anymore and we have school fees to think about. I understand her point, but part of me feels uneasy putting something unknown on a heavy car that carries our kids every day. A friend who works in a spare parts shop told me some aftermarket brands are made in the very same factories as the original ones, just in a different box. Another friend said that is a myth, and that cheap parts wear out fast and sometimes make strange noises. I tried reading about it and came across a post where somebody said a trusted Range Rover RepairRange Rover Repair garage will usually tell you honestly which parts are fine to save money on and which ones are better to keep original. That sounded like a good way to decide, but how do I know if the garage is being honest and not just telling me what earns them more? I also wonder if using non original parts can cause trouble with the warranty or when selling the car later. For things like brake pads, filters and wipers, is it really a big difference? And what about sensors or suspension parts, should I never go cheap on those? If you have tried both kinds, please tell me what you noticed after a year or two. Did the cheaper parts last, and would you buy them again? I just want a clear idea before I say yes to anything. Thanks a lot for reading, and sorry for the long message.