The best replacement for bitdefender is kaspersky.

The best alternatives to bitdefender are rated as following:
★★★★★  kaspersky
★★★★★  norton
★★★★  avg
★★★  avast
★★★  mcafee
★★  nod32
★  vipre
★  webroot
★  eset
★  microsoft security essentials
★  malwarebytes
★  avast free
★  avira
★  avg free
  norton 360
  norton 2014
  mse
  zone alarm
  trend micro
  sophos
  kaspersky 2014
  comodo
  panda
  zonealarm
  panda antivirus
  norton antivirus
  symantec

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

Other search terms related to bitdefender and their ratings are:
★★★★★ malwarebytes
★★★ comodo firewall
★★ comodo
You have in mind a companion for bitdefender and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of bitdefender in all years. Click on graph for more.
bitdefender
kaspersky
norton