the biggest factor between the two is mileage, thinking of leasing as renting a expensive ass car that you have to maintain still and you do not keep the car after the contract is up.
Luxury car brands often offer a full service leasing rate nowadays ... I made good experiences with Mercedes and Audi ... you pay a flat fee per month and everything - like insurance, service etc. - is included ... You will have a high rate but you're safe when anything happens ...