Well it depends how you bought your Juke, if you took a trailer load of cash into the dealership then no, there's no need for GAP insurance.
However if you've financed the vehicle you might want the peace of mind of GAP insurance. If your Juke is stolen/written off your insurance will only pay up to the market value for the car at the time of the incident (i.e. what it's worth). This could leave you in a position where you owe more money than the cars worth (negative equity).
Two of my friends have been in this situation, one with his X3 when it was stolen and burnt out.
The worst thing is to think you're covered, then something happens and you find you're not.
GAP insurance is exactly what it says, they will make up the difference between what the insurance pay-out and the out standing finance. Obviously every GAP insurer will have their own T&C's so its wise to read the fine print.
Hope that helps.
Edited by: iamdabe