1. ...the way it detects when one is traveling downhill (gyros?), and changes down a few gears automatically so that engine-braking saves one having to ride the brakes down the hill. My previous Merc didn't do this.
2. ...the way one has a choice of either driving on the edge, whipping past slower traffic but getting an understandable return of just 24mpg (GLA250), or hitting the Eco button, taking it easy, and getting over 40mpg. Max power or max economy - it's nice to be able to choose.
choice 1 is not on the 45 and must be very good off road... choice 2 have to agree but only 30 mpg if lucky flat out 19 mpg lol plus the high seat position is really good and one of the best sat nav's in the business...
Convenient Closing feature for sunroof and windows click lock button and click again hold button until sunroof and windows are fully closed... you have to do it on drivers side... pointing at drivers handle for it to work well.
3. ...the seats (AMG line, leather, with adjustable lumbar support). I've had spine surgery and am 6'3" tall, and used to fit a lumbar device to my last car. The seats in my GLA (with lumbar set to maximum) are just superb in terms of comfort and support - no other car I've tried comes close.