BUYING

Full proprietorship at the end of the loan - If you finance the purchase with a loan, your monthly payments will be determined by the vehicle price, the interest rate on the loan, and the length of the loan. When you complete the last payment on the loan, you'll own your car and can choose to sell it or remain driving it.
No limit on mileage - Leasing is stipulated at giving you a lesser payment... which means a limitation on mileage. When you set the lease up, it's hard to determine how many miles you'll use during the life of the loan. Mile overage charges can be very costly.
Less worry about dents and dings/condition - When you own your vehicle, it is your property. You will not have to worry about turning in the vehicle in flawless condition because no one owns the vehicle except you.
Flexibility to customize your vehicle - Many owners prefer their vehicles a little more upgraded than the stock configuration. If you prefer aftermarket stereo system, racing stripes, fuzzy mirrors, or something more drastic, buying is your best option.

LEASING

Reduced (or no) down payment - Getting a great payment is paramount to making a car affordable. With leases, money goes further. Usually lease agreements include various options to choose from, many with little or no down payment, while still keeping the monthly payment low.
A new car every few years - Since leases are designed to utilize the most practical period of a vehicle, you will seldom have to worry about maintenance or components of the vehicle failing, warranting expensive repairs.
You can drive a better car for less money - When you lease a vehicle, you're only paying for the portion of the vehicle you use over the course of the lease, which usually lasts two or three years. Because you're not making payments based on the entire value of the car, your monthly payments will be lower.
No long-term commitment - With some financing options, you may be forced into a 60, 72, or even 84-month payment plan to get the payment you want. Leases give you the flexibility to restart another agreement on a vehicle you want to drive. Less commitment means more freedom.