The Sennheiser G3 comes with an ME2. The MKE-2 is an upgrade. The ME4-N is a cardioid patterned mic. As such you have to be very careful with placement. If the mic isn't aimed at the speaker's face, the sound won't be ideal. It's better to center mount a cardioid lav on a tie or shirt plackett.
Some lavs are so directional that head turns are a problem.
You also need to be careful about nose snorts and down breaths. Directional mics are much more susceptible to them than omnidirectional mics.