For a long time I treated white shelves the way I treat white couches: a trap for people with more discipline than me. Everything on a white shelf shows up, the dust, the smudge, the mismatched spines. What changed my mind was finally putting a set up in a rental with beige walls and dark trim, where every other shelf I tried looked like it was apologizing for being there. White just stopped arguing with the room.
Where they get tricky is next to warm wood tones that are trying to be the main event, a honey oak floor or a walnut sideboard with real presence. Put white shelves right above or beside one of those and it can read like two different houses mashed together, especially if the shelf has any modern edge to it while the wood piece is older and softer looking. They also fight with walls that are already off white or cream, because then the shelf looks slightly wrong instead of clean, like a shirt that's not quite as white as you thought under store lighting. They do best against a wall with some color or against exposed brick, somewhere they can actually read as a deliberate white rather than an accident. The other thing worth knowing before you buy is that white comes in a dozen different whites, and the one on the box photo is rarely the one in your hallway.
In the shop, or the second it arrives, check the finish close up under real light, not the display spotlight. Matte white shows fingerprints less than gloss but scuffs easier at the edges, and a laminate white chips at the corners in a way that's hard to touch up without it looking patched. Run a hand along the underside of each shelf too, cheaper ones flex if you load them with anything heavier than paperbacks, and you will find that out the day you put actual books on them, not before.
If you've never owned a white shelf and want to start with one, go basic and boxy before anything with open backs or fancy ladder angles, a simple bookcase with adjustable shelves teaches you what you actually want to store before you commit to a shape. The detail that makes a good one worth living with is the paint matching the trim in your room closely enough that from across the space it just disappears into the wall, and you only notice the books.