I love the unit. So easy to use and very durable. I went with 4 stars instead of 5 for a couple of improvements I would suggest -- t1) he bottom tray always lags behind the others in food getting completely freeze dried. Is there a way to fix that? 2) Removing and changing out the tray unit is a little awkward and 3) Anyway, given the no lip on the trays, to design a tray cover/stacker that would fit over the trays? These items are nits -- it is an awesome machine. I would by another one in a heartbeat.