i picked satin (didn't know about the dust on glossy) because it looks more 'comfortable.' just like a home that's a little bit lived in. you sit down and are not scared to sit with jeans. of course, i don't even have a grand piano.
i have a kawaii studio upright (which i love!!!) it has a satin finish.
the solution to dust is to buy or make a cover. that way, your strings don't get dusty too. my old french piano prof. was very particular about the school pianos at university of alaska and kept as many as he could in good condition by telling his students that (after practicing) he expected them to shut the lids, and put the covers on. am dismayed now, when i see perfectly good pianos get destroyed in a year or less (school pianos) just because it is thought that noone will do this. college students aren't highschool students - and i think they can handle the responsiblity (do i sound like a mom?)
ok. another pet peeve is that practice rooms and some music halls have absolutely no decoration (bland colors - usually white). since the art depts are usually close by, why don't they cooperate with each other and have music students play during art exhibits, and art students come and do a few art murals on the blank walls. just an idea.