I have an old Samson CT-3 that don't use much anymore because of the poor signal-to-noise ratio, and the slight delay that throws my timing off. Newer models from a lot of manufacturers perform much better in both categories.

As for interference, that shouldn't be much of a problem, if you're careful about selecting the channel you use. Obviously, if you set up on the same frequency as the local FM station, there's going to be trouble.

A good system uses two antennas on the receiver to enable a technology called 'diversity' reception. This is a technique that was developed for mobile receivers (like car radios) to reduce the multipath distortion that results from reflected signals arriving at the receiver out-of-phase with the direct signal. This particular feature does not prevent interference from other sources, but it does provide a cleaner sound.