 I stepped up from a 2006 530i and must say the new 750i has noticeably more power and acceleration.  It is extremely quiet at all speeds (I sometimes have to look at the tachometer to make sure the engine is running).  I haven't put it completely through its paces yet, but accelerating onto the highway is no effort.  I guess with 0-60 in 5.2 seconds I shouldn't be surprised.  I love the electronics and find the iDrive much easier to use than my 530i.  This vehicle is rock solid and top quality.   