Benefits:
 
Starting with the obvious, it is important to adequately save for your retirement, particularly as we are living longer. You want to give yourself the best change to comfortably live through the fifteen or so years you are likely to spend in retirement.

The tax benefit is also clear. The Inland Revenue basically returns the money you have paid in taxes on the amount you are saving. What is more, you pension does not come under capital gains tax as it would if you decided to pursue other ways of saving for your retirement.      

Drawbacks:
 
The obvious major drawback of a pension is having your money kept away from you until you retire. You have to keep putting money away for a number of years.
 
One of the most talked about problems do with pensions at the moment is that fact that individuals, by law, are currently forced to buy an annuity when they retire. When interest rates are low, this can go against you.
 
Your pension could also be negatively impacted by high inflation. In most cases, your pension fund should be ahead of inflation, particularly if its invested in asset classes like equities, which most funds are.
 
To minimise the risk of inflation, upon retirement it is possible to look around for an inflation-proof annuity. However, you will have to pay a premium for this.