paul.r i have recently used dr.web antivirus for about a month and i would like to share my experience with you.
pros:good detection,nice web blocking, you can install firewall if you want,frequent updates.
cons:about 160mb of ram,slow quick scan(on my system was taking about 20 minutes to finish),web blocking(i think it is called spider guard or gate i don't remember exactly)was a little aggressive i mean it was blocking components of legit sites and i couldn't have access to them.
p.s. my laptop is more than five years old so it was a little heavy on my system but not much.if your pc is much newer i don't think you will have a problem.
p.s.2:a big plus(for me at least)you can choose which components you can install(especially if you have dr. web security space)for i didn't install mail guard and parental control and the firewall.of course all this through custom installation.
p.s.3:the firewall is good but in the beginning you will have a lot of pop ups it's not like kaspersky firewall or norton which take decision on their own.if you don't have problem with pop ups use it because it's pretty good
i hope my answer will help you