For all the various brands of wiper blades I have tried on my cars through the years I still find that a clean windshield and OEM blades are most often the best choice.
During our winter rain season we pretty much have to use our wipers every day and the main problem fro getting good results from my wiper blades is almost always the crud that gets tossed onto my windshield from the roadway. I like to use a deep cleaning window prep like NoTouch Auto Glass Stripper or Glass Science Glass Scrub to get the windshield really good about every 3 or 4 weeks during our wet season. I typically will clean my windshield with a good window cleaner like Invisible Glass or Eimmannn Fabrik Clean Vision every morning before heading out from my garage - even when it is pouring during the winter or whenever I know I might need my wipers that day. This gets yesterday's grime off of the glass before I start trying to push the wiper blades across the surface to do their deed.
If you care for them, the BMW OEM blades work great and the best part is the fact that they are amazingly cheap. I don't know of any aftermarket wiper blade that costs less than the replacement blades from the dealer.....