We have one – it works, but in our case, the condensation is usually around the window edges*, so you have to wipe anyway.
*I've never figured out why, I'm sure there's a reason, but the condensation is always along the bottom edge, occasionally creeping up the side, but never in the middle of the glass. I assume there's a small temperature gradient towards the edges of the sealed unit and water vapour is heavier, so the process starts from the bottom.