Here "system roll back" refers to an interesting feature of the Proactive-Defense/Behavior-Blocker module of Norton (Sonar).By the way i didn't know that Norton has a roll back feature
and I get pulled over for excessive smileys lol that's too funny!I can't say anything about BD Antivirus Plus since i haven't tried it ( although i am looking for a license).
One thing i can say for BD in general is that they have improved lately in the system performance section.
I mean that the latest versions of BD are lighter on system resources.
About Eset i have to say that is very light on system, it has great detection
but you have to play with HIPS settings to have better protection.
Another plus of Eset is that it has zero impact on boot and shut down time on my system.
Overall Eset is a great software.
Emsisoft also has very good detection and it also has a Behavioral Blocker which is very useful when signatures missed a malware.
Emsisoft 10 has improved a lot on system performance and from my experience is very light on system, the same as Eset.
Another plus for Emsisoft is -that if you are running a low memory pc 1 or 2 GB of RAM- it uses less RAM than Eset about 20-30 MB.
Emsisoft uses more RAM when it's updating and while scanning the system.
Emsisoft is a set and forget software.
I hope i have helped.
P.S: the best software for me would be Eset with Emsisoft Behavioral Blocker