I've been using Braun battery powered shavers for about 10-12 years primarily finding them at Walmart or Walgreens for about $10. The model 5615 and earlier ones provide a much closer and smoother shave than the M60. The foil heads on the 5615 last me about 1-1/2 to 2 years before they develop worn openings or holes that cause sharp pains like a nick or whisker pull, but prior to the holes they perform excellent. The foil in the M60 and other recent models seems to be made of a little thicker foil and have different designed openings I assume to make the foils last longer. These razors do not provide near as close or smooth of a shave and require a lot more strokes and time to provide a noticeable shave.
I wish they'd go back to the screen types used in the 5615.