Been looking at them recently but not yet purchased.
From ginge's link "Despite both having 'fryer' in their name, air fryers and deep fat fryers work quite differently. Air fryers are often referred to by manufacturers as healthy or low-fat fryers, as they use hot air and a small amount of oil to cook the chips. The results are more akin to oven chips than traditional chip-shop chips."
Oh.... may as well stick with oven chips then. Whole point is to achieve a better result, not spend a fortune to end up with the same thing :-(