What is the difference between UHF and VHF?
VHF microphones are great for family fun and singing in a large living room or small recreation room. As long as you stay within 100 feet of the base unit and maintain a line of sight with the antenna, you will get good reception. For most home uses, this typically provides a clear enough signal, although some electronic devices like blenders or microwaves can cause interference. We don't recommend you sing Karaoke in your kitchen anyways. But for your house party, tailgate party or relaxing evening at home the price is right for VHF wireless mics; they are typically around $100 or less for two microphones.
UHF microphones are professional quality microphones; the kind you see on a professional sound stage, on TV shows and in concerts. Their range is several hundred yards in many cases so the singer can walk quite far away from the transmitter and still get good reception. Unlike VHF microphones, there is no need for line of sight between the microphone and the transmitter. You can typically go into an adjoining room and still get great reception without worry of interference. Being designed for professional use, if you ever do experience any interference most UHF microphones allow on the fly channel switching, allowing you to find an interference-free channel. If you want to run a great karaoke show or have simply the best vocal experience, then get a UHF microphone set in one or two pairs. The difference in quality and options will more than make up for the difference in price.