Great, but watch out for escape artists
We've owned the standard SureFlap microchip cat flap for a couple of years and recently upgraded to the dual scan after getting a 6 month old Bengal kitten as we wanted to keep him indoors whilst allowing free exit and entry for our existing cat. Build quality of the updated flap is of the same high quality, if not slightly better with uprated draught exclusion.
The principle of the dual scan is excellent, however the Bengal learned within 2 weeks that if he follows right behind the other cat whilst he is going outside, the kitten can get out too before it latches. So, a good product but if it's critical that a cat stays indoors, don't rely entirely on the cat flap to keep him in.