Differences between the ModMic Uni, USB, and Wireless
The ModMic Uni has a 2-meter cable (shorter than the ModMic 4's 3-meter cable), an improved uni capsule, and no problems with RF signal interference. Note, it is unidirectional only and does not have an Omni capsule.
The ModMic USB and ModMic Wireless would be the best option for both uni- and omni-directional mode that doesn't pick up as much RF interference. It is up to personal preference whether or not you’d like to have a wireless mic. FYI, mounting a wired mic to wireless headphones runs the risk of putting too much stress on the mic cable, leading to issues with the microphone.
Between the ModMic Uni, the ModMic USB, and the ModMic Wireless, they all have the same Unidirectional capsule; however, the ModMic USB and the ModMic Wireless also offer an omnidirectional capsule (for studio quality sound) that is popular among our users.