Can't speak highly enough of the work Eureka did mounting my Elfa bookcase system to an old, weird plaster wall. After they got it on the wall we realized that the top rail of the system we'd been sold was too long for the width of the shelves, which looked pretty bad. The installer pointed it out and cheerfully offered to remove it from the wall, cut it down to size, and then reinstall it. He also drilled new pilot holes through the rail and secured the system at multiple extra points (going beyond the installation instructions) to make sure everything was as stable as it could be. They also mounted a number of other hooks, windows, and shelves around the house during the same day of work.
They were also very careful and professional about COVID safety both during and before the appointment. (I hope that it's not long before this part of the review is no longer applicable!)