Placing things seems to work a little less than half the time. Worse if it's underground. And there's no undo button, so you'll often end up with two of the same thing on top of each other. You can demolish one and get back some percentage of what you spent though, so it only costs you 30% (or whatever) per attempt every time the interface is screwy and doesn't allow you to connect the things you're looking to connect.

It's like Legos if every piece was a slightly different shape and none of them were 90 degree angles.