Webroot is lighter than BitDefender, however, it's optimized for
companion AV (See
@Umbra Polaris guide:
http://malwaretips.com/threads/how-...-antiviruses-in-same-time-and-set-them.23954/). So you can use it along with BitDefender or use it as your only security.
My suggestion is to try Webroot, it might be good, it might disappoint you. For me it's a light and nice addition to my security configuration without any problems, but some people have been reporting issues with computers not fully shutting down with Webroot. It's a 14 day trial, but I have 180 day key, PM me if you want it
Overall, you should try it to see if it works.