We bought the Ninja 15 in 1 about 14 months ago and whilst I was a little worried that it would become an expensive cupboard ornament, (We paid about £250) I am so glad my wife talked me into it.
We use it for so much, including cooking large joints on the steam roast function for melt in your mouth meat, par boiling roasties on the pressure function for 2 minutes and perfect results, fantastic bread, using both the prove and steam bread functions and amazing crackling covered pork joints using the roast function and temperature probe. It is also brilliant for all of the normal air fried stuff. So quick and so cheap in comparison to the normal oven.