IMHO wired systems will always consistently outperform wireless. That’s not to say they’re superior, but due to the solid connection, depending on the quality of the system, it will “consistently” outperform all but the most technologically advanced wireless systems.
You can get excellent quality audio from a wired lapel system even using the Radio Shack brands and save yourself some bucks in the process. For $800 or so you could invest in a Sony wireless system that is hard to beat – UWP-V6 in fact all the UWP series is worth checking out to determine the extent of your interview mic needs.
