You absolutely MUST get independent financial advice before you do this - in fact the law requires you to do so and get a certificate of advice before your employer will b allowed to make any change.
It ll really depends on your circumstances - how old are you, how long do you expect to live, are you good health, are you married or with a partner, do you have young children, have you got a mortgage or debts, what would you do with the money ie where would you move it to. What is your attitude to risk - would you be angry if the size of your pension pot shrank?
If it is a final salary scheme (Defined Benefit) in general you will be much better off leaving to where it is. You would be hard pressed to get the rate of return on the money that a good set of pension trustees are achieving. If money purchase scheme (Defined Contribution) it will depend on scheme. The sweetener offered by your employer may be attractive - but they obviously want people out of the scheme for some reason so you really need to understand why. Is your employer stable and secure?
In DC you can take all your pot at 55 and more or less do what you like with it - but remember it has got to provide for you and any dependents for the rest of your life, and maybe their lives after you die. ie you need a lot of money!