Choosing between a VHF frequency or UHF frequency depends on what you are going to use them for. VHF is mostly for outdoor use where you are free from obstructions. The frequencies of VHF travel further if they are not disrupted by barriers. The only time you will want to use VHF is if you are outside in a wide-open space like a field. VHF has smaller frequencies which means interference with other radios is common.
UHF, on the other hand, is an all-around better signal for long distance communication. UHF is better when using radios for indoor use like buildings or around cities. A plus to using UHF is you are less likely to be interfered by other two-way radios. The reason why UHF is better for inside use opposed to VHF is, UHF signal does a better job at reaching through wood, steel and concrete, therefore, can reach further into the building.