Choosing a UHF antenna is quite easy - unlike mobile phones where you have different frequencies, all UHF/CB radios transmit and receive on one frequency - 477MHz. Often the choice is actually more about practicality - for example, is flexibility important?
Which UHF antenna is best for me?
The choice of antenna depends on the area you're travelling through. While a higher gain means a stronger signal, when you increase an antennas gain (ie it's dBi), the angle it can receive from is reduced - this means that high gain antennas are more suited to flatter areas, and moderate gain antennas (such as 5-6dBi) better suited to hilly areas.
Which brand do I need - RFI or ZCG?
ZCG Scalar bullbar antennas are designed with solid copper radiating elements, designed to last on even the toughest of corrugated roads. You'll typically see RFI brand antennas on fleet and emergency vehicles in regional and rural areas because of their excellent performance for a very reasonable price, but if you frequent unsealed roads or rough terrain ZCG's UHF antenna series are the preferred choice.