You can stay exactly where you are, and in the long run, it might also be the cheapest.
You might end up saving $10 and having cleaner wheels, but if you want to save the $10 so you can have your car washed every day, you're sort of putting the cart in front of the horse.
Also, I can't recall reading of anyone that has gotten the wear out of my OE pads...and although a pad might seem as good as OE, it might also be wearing out the rotors significantly more. Personally, it doesn't make sense to me to try to engineer the brakes on a car like a bmw. Sure on a Yugo I might, but BMW is a pretty good car, you know. I think they got it right.
If you're an automotive engineer, then I'm sure you'd do okay re-engineering our brakes, especially with all the anecdotes you'll get of great 'other' pads. You understand there's always going to be a bit of bias involved when it comes to recommendations here. If someone gets pads because they don't like dust, and the pads still stop them, they'll 'feel' they're as good as or better than OE, because they want to feel good about the decision they made...that dust is bad and stopping usually isn't that important anyway.
Just saying. I say OE because I'm not an engineer, but I know they'll stop the car--in rain, snow, day, night, hot, cold, smoothly, evenly, and quickly. Why do I know? Because I've trusted bmw brakes since 1994 and they haven't failed me once...except that one time when they stopped me too fast!