Leasing is good if you are either self employed or run a business, which is what this type of arrangement is aimed at. This is because the majority of the lease can be written off against tax if you are self employed, and all of it if its a business. The difference being (with self employed) a proportion of the time it is considered to be for private use, with a business you can say it is solely for business purposes. This of course gets added into both your profit/loss and cash flow balance sheets as a fixed monthly amount out. This makes it easier for a business in many ways, since there is no depreciation value to add in.
The other fact with lease hold is that you never actually own the item, so a service charge is usually added into the price, to cover servicing costs.
Whenever you consider something like this, you need to take everything into account and look carefully at the contract, Some companies will fob you off by calling a contract lease hold, when it is nothing more than a HP contract in disguise,or as Azzy has said above a PCP.
The majority of lease hold vehicles have a term time, at the end of which you give the vehicle back and get another new vehicle.