The first app I tried was Living Room. I fiddled with this for a while, and then got frustrated.
• I felt I didn't trust its representation of measurements, because my 1-foot-deep bookcase didn't fill a 1-foot grid.
• I couldn't align objects easily, so the walls of my model room didn't match up.
• The color selection for objects doesn't have an accessible brown. This makes it really hard to tint my wood-grain objects.
I then decided that I could blow another ten bucks splurging with other apps, and tried Home 3D. The big feature that this offers over Living Room is the ability to see your rooms in 3D. I found the flow of this app easier to handle than Living Room, once I grasped their quirky UI idiom - but I ran into other troubles:
• I couldn't change the colors of objects at all. (Oddly, this annoyed me less than the lack of browns in Living Room.)
• And the clincher that made me put the app aside, at least for a while: it has no models of bookcases, not even in the extra models available for in-app purchase. These creators are clearly not developing for the interior design challenges I face.