We have one, and soon we will be getting a second exterior lift-sliding door.
I like them because the sliding doors are out of the way – easy to use, but every now and then I think about the fact that a brushed system can't insulate well.
Although I have read that they are very tight now. I'd be interested in comparing the insulating effect of the lift-and-slide and "regular" doors.
Does anyone know where to find the information?