The OE eyecup is fine but can get knocked off easily. These are a decent substitute that can handle a lot more force before coming loose. There can bit of display light leakage at night with this eyecup to be mindful of.
Amazon product ASIN B00FG8B474View: https://smile.amazon.com/gp/product/B00FG8B474/
Amazon product ASIN B00FG8B474View: https://smile.amazon.com/gp/product/B00FG8B474/