The best replacement for omni is cardioid.

The best alternatives to omni are rated as following:
★★★★★  cardioid
★★  zaft
★★  virtualizer
★★  apollo
★★  mecanum
★★  uni
★  clan
★  directional
★  nason
  cm
  new frontier
  shopline
  guide
  touchsmart
  aokp
  yagi antennas
  cardioid lavalier
  hercules rmx
  yagi antenna
  cardioid mic
  yagi
  ritz amelia island

Your alternative for omni is not listed? Suggest!
Speaking about omni, one probably shouldn't forget about oculus rift.

Other search terms related to omni and their ratings are:
★★★★★ oculus rift
You have in mind a companion for omni and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of omni in all years. Click on graph for more.
omni
cardioid
zaft