Good, But....
....They are a LARGE appliance, big as an old '70s microwave, and of real use (at least in my kitchen) only several times a year.
They're great for critical baking, and they do roast in less time than a conventional oven. But the footprint requirement means that mine is kept in the basement, and brought up only as needed.
P.S.: If you get one, be sure to put the filter through the dishwasher after each time you roast meat. Otherwise, the filter stinks up your kitchen. It's easy to forget the filter while you're cleaning everything else.