We have them in our house, installed by previous owners (Daiken brand). Reading the above posts about cleaning issues has made me realized that we need to check on whether we're keeping up appropriately. So far they work fine for us. They are in each bedroom and there is one downstairs in our family room that is open to the kitchen. If we were in a hotter climate I could see how that might not be enough, but here in New England it's fine for our needs.
We also run them as heat units in the winter to supplement the baseboard heat- since we have solar panels DH thinks it is saving energy. I'm not sure. If we were relying on them for heat alone it wouldn't be great- since the units are up high and hot air rises, you don't get as much benefit.
They are ugly but usually I don't notice them. But they get in the way- the unit in our room is on the window wall, and is in the way of doing curtains (previous owners had blinds and I'm going to replace with Roman shades). The downstairs unit is where I might have put built ins or a fireplace on our family room wall (can't believe our NE house has no fireplace).
Jen, mom to "Little Miss Tiny" 4/07