 Consider what comes standard on the series.  What features are most important to you and what you can afford.  I wanted the horsepower of the 750 but opted for the 740 because of the actual improbability that I would be racing the car..:)..so far I am beyond impressed and don't want to get out of the car.  I will say that the interior feels a bit of less quality  than my 550...which was built in 2008.   They have made some other refinements that balance the overall experience.  I am a lifelong bimmer enthusiast.Update: 6/14/16I am in love!  I really have no complaints about the car.  I did have to add radiator fluid...which is weird for this year model.  I will see if that problem repeats itself.  So far so good!  The learning curve is sharp with this car as the technology is very advanced.  I must retract my comment above based upon horsepower because I have now driven the 750 and the difference in driving experience definately does not justify cost.  Overall, really content with my purchase!I still fell the same 2 years out....onlu complaint is front window noise that I swear occurred after i had the windows tinted in 2015.  It's been checked and still no resolve.   The whistle sound on the highway drives me slightly nuts.