I never used a mechanical keyboard to any real extent, but I do remember the guy that thought he was so cool at the tech support job I used to work at. He brought in one of those old IBM keyboards and it was loud as hell as he typed. It became so irritating to everyone around him that management made him take it home.
I can't stand the loud sounds of some of those mechanical keyboards, especially if I'm not the one using them.
Kind of like noises from people chewing. I cannot stand to hear other people chew, but if I'm eating with others, the sound doesn't bother me. Same with those keyboards, if I'm busy typing away the sounds of a keyboard doesn't bother me, but if someone else is typing and I'm in the room...the sound starts to irritate me. I can stand there and listen to nails on a chalkboard all day long, but the sound of chewing or keyboard clacking just gets under my skin.