It's relatively easy to cut down a Billy to fit an awkward space.
Sadly, that isn’t the problem. Two Billy cases are short (wasting room height) and too narrow, but the space between then isn’t big enough for something useful like a shiny discs unit or something. By contrast, 2x Ivar fit almost exactly (but are a bit high for our absurdly low downstairs ceilings).
You know what grinds my gears... that IKEA doesn't allow for skirting boards at the back of their bookcases. (I know wrong thread!)
Our Billy cases have pre-made cuts for skirting boards. But they’re really old ones (c. 2006) and so I guess things changed with the new, shallower redesign.