I have used BitDefender since 2013 and its firewall software caused many (still unsolved) problems with Windows: ill-supported IPv6 (Windows does not get IPv6 addresses), blocked homegroup, unstable adapter setting, unusable stealth setting, etc. I was so fed up, I decided to uninstall it (while I still had one year license) and I ordered ESET Smart Security 8 and now Windows 10 works like a charm: no problem with homegroup, I have my IPv6 addresses, etc.
In short, BitDefender damages your Windows experience in such a way it becomes intolerable, ESET keeps it intact. Now when I read all the positive reviews about BitDefender, I can only think that those reviewers never used BitDefender on a daily basis.