It is worth getting the polyurethane bushes as they are not affected in the same way rubber bushes are with fuel, oil, dirt, and even warm or cold temperatures.
Be careful when buying though, each individual bushed component has a "Shore" rating, basically this is its hardness or compliance, and each component has a different shore rating, shock absorbers shore ratings will be different to the anti roll bar bushes shore ratings.
Many aftermarket suppliers supply uprated shore rated bushes, and they will all be the same shore rating, irrespective of whether they are for a shocker, anti roll bar, or bottom suspension arm, these uprated bushes will often make the suspension less compliant, and the ride harsher as they transmit more vibrations then the original shore ratings. Less compliance in a 4X4 suspension is a definate no-no when it needs its compliance, and the extra noise and vibration on longer or high speed journeys can be tiresome and irritating.
Stick to the market leaders of polyurethane bushes, they may be more expensive, but they will provide standard and uprated variants of the poly bushes, and they will come as a kit with each component marked for its specific application, and also consider once poly bushes are fitted they are there for life, so a little more cost is nothing.