Digital wireless systems such as the newer XVive products have around 6 milliseconds latency. That's not necessarily a problem but, if you combine that with a digital FX pedal such as a TC Helicon Play Acoustic/Electric you might get annoyed and frustrated by a quite noticeable lag from the time you pluck a note and when you actually hear it. So, check the specs on products and keep that in mind. You might get a digital wireless gadget now and connect it to your analog equipment and have no noticeable latency. Then later you add a digital FX gadget and think the problem is solely with the newer gadget since you didn't notice it before. I am speaking from both; seeing someone else have this problem and I myself must be really susceptible to noticing latency while playing live even if its someone else with the latency problem.

Does the noise in your head bother me ?