I love mine as well. IF yours aren't working properly... you might ask your dealer if they can reset the calibration for the "rain sensor".
Recently on my e39 the intermittent wipers would only work at one interval - always at six seconds. (that car has a thumb wheel on the stalk and you can vary the interval). But the interval was always the same no matter where you turned the thumb wheel.
I asked my dealer about it, while doing some other work for me... they recalibrated the rain sensor and now it works GREAT! So I would try that.
Btw... have you ever had the windshield replaced on your 1er? They should have replaced the rain sensor when replacing the glass windshield. I know my insurance company tried to weasel out of that cost. They paid in the end.