What are the advantages and or disadvantages of wireless UHF/VHF mic systems range, reception, interference etc...?
UHF has less to compete with for bandwidth, and suffers less from electrical/electronic interference. UHF uses more battery power and smaller aerials. You can also extend the range more with UHF using specialist aerials. If you can afford it UHF is usually the better solution.
Historically radio transmission has been moving up in the frequency spectrum
you may expect better quality and lower power requirements (higher battery life) from UHF, but the experts say the benefit is usually less battle for channels and smaller antennae.
Familiarise yourself with the legalities of the spectrum distribution, as that's a minefield just as well.
http://www.gbaudio.co.uk/radio.htm - here's the UK version. Other countries have it different.