The best replacement for backtrack is kali.

The best alternatives to backtrack are rated as following:
★★★★★  kali
★★★★  blackbuntu
★★★  metasploit
★★★  backbox
★★  beini
★  wifislax
★  pentoo
★  mkb
★  backtrack
★  xiaopan
★  arch
★  arch linux
★  gnacktrack
★  wifiway
★  matriux
  reaver
  aircrack
  nst
  fedora security lab
  rman
  kali linux
  knoppix
  back box
  back track

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

Other search terms related to backtrack and their ratings are:
★★★★★ reaver
★★ spoonwep
★★ aircrack
★ usb wifi
wubi
metasploit
You have in mind a companion for backtrack and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of backtrack in all years. Click on graph for more.
backtrack
kali
blackbuntu