Shimano pads were removing pieces of aluminum from the braking surface. Some ended up in the pad itself, damaging the rim even more with each stop. The surface of the rim was looking like someone took a 60 grit sandpaper and used it on it. Your rim will last much longer with good pads, and clean braking surface from mud or sand. Koolstop pads supposed to be easy on the aluminum rims. I'm very happy with them so far. Just keep your rim clean and enjoy the ride.

Oh...one more thing. Adjusting brakes is a very easy thing. No need to take it to the mechanic. You can browse bunch of different YouTube videos about the maintenance of the bike, and start doing stuff yourself.