They are totally hard to figure since both good on zero day and rather few links miss, perhaps less than 5-8 samples should be your expectations to the test.
Same features with no exception list function to obtain possible mislabeled websites.
BitDefender As I tested both and mcafee seriously missed a lot of malicious sites while bitdefender captured and blocked them and bitdefender has better zero day protection as @jamescv7 already mentioned it
I've debated using these as well (I used to and still have the Qihoo extension enabled) but I wonder if, after DNS, Chrome or IE's filtering, AdGuard filtering, could anything possibly be left for extensions like these?
Well, I'd go with BD TrafficLight since I've found it to be more effective in detecting malicious URLs. Also, it scans a site in real time, while McAfee offers just ratings. On the downside, TL seems to slow down browsing more than SiteAdvisor.
The supplement of the Google Safe Browsing is still on the improvements to accumulate more blacklisted sites, so having a security extension isn't a bad idea unless use IE for the smartscreen filter.
But I dont use Webprotection extension/addon. I install AV & if it has Webprotection fine & if it doesn't have Webprotection then I dont install extension/addon for Webprotection. Just rely on browsers protection & ublock extension for ads, etc...it has phish/mal too but guess not that good.