What's been the trouble with the Aztecs?
I've had a couple problems with Azdens, but eventually got them fixed when I returned them to the shop.
UHF mics are subject to problems the further you are from the transmitter. Sometimes thirty feet is too far. VHF mics tend to travel better, but with fewer channel choices.
There are several companies out there making video type wireless mics, but I don't know of anyone using anything other than Azdens.