Range: VHF vs UHF
In any radio system typically all the radios operate on the same frequency and therefore in the same radio band. A Band is a spectrum of frequencies. All the bands pretty much do the same thing but they do have slightly different properties.
Commercial two-way radios in the UK use one of three bands.
This is by far the most popular band because the signal penetrates buildings better than the other bands. As most radios are used in urban areas it more UHF radios are sold.
VHF High band
This is the second most common band and works better than UHF in open country but is quite usable in urban areas too. I will give slightly better coverage in undulating country with the signal being reflected and refracted slightly around and over hillsides.
VHF Low band
This band is the best for open country but performs poorly in urban areas. It has a long wavelength which means efficient aerials cannot be made for hand-held radios so is only really practical for vehicle only radio systems and is therefore not commonly used.