The best replacement for x12 is x32.

The best alternatives to x12 are rated as following:
★★★★★  x32
★★★★  x11
★★★★  xl1
★★★★  edifact
★★★★  px22
★★★  g230
★★★  px21
★★★  z22
★★★  hl7
★★  z11
★★  x42
★★  dx12
★★  x41
★★  x31
★  siberia v2
★  tritton detonator
★  p11
★  x14
★  rf 1200
★  x16
★  tritton trigger
  x11 turtle beach
  tritton
  rf1100
  skullcandy slyr
  detonator

Your alternative for x12 is not listed? Suggest!
Speaking about x12, one probably shouldn't forget about dss.

Other search terms related to x12 and their ratings are:
★★★★★ dss
★★★★ astro mixamp
★★★★ dss2
★★ mixamp
You have in mind a companion for x12 and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of x12 in all years. Click on graph for more.
x12
x32
x11