New BMW M5 vs Mercedes-AMG E63 S

Buying and owning

Costs, equipment, reliability, safety and security

You’ll need nearly £90,000 to buy either car with cash, and because the M5 has only just gone on sale, BMW won’t give you a penny off. Haggle with Mercedes, though, and you’ll be able to get the price of the E63 S down by about £5000.

That goes some way toward the Mercedes being the cheaper car to own privately over three years, by nearly £8000. Better fuel economy (its V8 can run on four cylinders at a cruise), cheaper insurance and slower depreciation help, too.

The Mercedes is also cheaper if you’re buying on PCP finance. Stick down a £10,000 deposit on a three-year deal, limited to 10,000 miles per year, and you’ll pay £1367 per month, compared with £1508 for the BMW.

Both cars get a huge amount of standard kit, although a powered boot-lid, a sunroof and keyless entry are all included on the BMW but options on the Mercedes. The same goes for safety kit; both get automatic emergency braking, but the BMW adds cross traffic alert (which brakes if it detects traffic crossing behind you as you’re reversing), blind-spot monitoring and lane departure warning – all options on the Mercedes.

Even so, these cars’ everyday counterparts (the 5 Series and E-Class) received five-star ratings from Euro NCAP, while security firm Thatcham rates them as excellent at standing up to a break-in and good at resisting being driven away by a thief.