Just an observation, my AB wipers did the same thing after installing them. Missing spots on the windshield and it seemed like the wiper was not contacting all of the glass like it should. I found that after adjusting the wiper arms and tightening up the nut they eventually worked fine. Ive been using AB summer and winter blades for a year now and they do work, they need need time to break in and contour to the windshield. Currently Im using the winter blades and they work great so far. Replaced the rear wiper blade as well with AB and I have no complaints. In fact the rear wiper blade has been the least problematic of all my wiper blades! Maybe I got lucky.

 

Bought my disco a month ago and it was missing the rear arm. Bought arm and blade from AB and it works as good if not better than the D1 arms and blades on the front.

 

My observations over the years are if you live in a moderate climate the standard blades are OK. If it's very hot and wet they are also OK but the sun and heat degrades the rubber blades quickly, always keep a spare set. If it's a heavy snow area take the other guys on here's advice as they will know far better. In overnight freezing lift the blades off of the windshield. Never try to start the wipers when they are stuck to the windshield it'll ruin the wheel box's or motor. Keep the wiper arms serviced and free moving at the hinges with WD40 or similar and ensure the blades articulate properly and contact the screen properly. The same goes for the rear wiper also. If the rear wiper motor stops, take it off and grease the internals and spray the wiring plug and socket with WD40 or electrical contact spray. I use the latter on all plugs and sockets on the truck particularly the ECU's.