Firefox extention-Avast Online Security vs Web Shield

I tried out Avast Online Security extension on some malicious test sites. In each case, the avast web shield responded, but the extension did not respond. This raises some questions for me:

Could someone explain the difference between the extension and web shield?
What value does the extension provide over the web shield?
Does the extension slow the opening of web pages?

Thanks for the help.

Web shield is the major shield while online. It blocks viruses and other malware.
The AOS is along the same lines as WOT and is based on user input.
No, the AOS does not slowdown surfing.

Thanks for the help

AOS is more than just user reputation - it also checks for phishing pages, corrects some mistyped addresses etc. So it does other (also security-related) stuff that Web Shield doesn’t do; on the other hand, it doesn’t scan the page content for malicious code, that is up to Web Shield.
I suggest to check the settings of the extension, you’ll see the features.

I found the settings which I hadn’t discovered before. Looks like some good things. If it doesn’t slow down web pages, then it is probably useful. I have an old computer so I don’t like to put it under undo strain.

Thanks for the help again.