The free version of this (I've never paid for it) is very good. I mostly use it for ad blocking with only the occasional scan for viruses. Ad-blocking-wise, it is very, very good. It even blocks the ads on youtube, though it takes about two seconds for the page to reload after it blocks the ad.
It hasn't yet caught any viruses on my laptop, but that might be because there are none?
The virus scanner only takes like five minutes and it can run in the background while you do other things.
All in all, I really like malwarebytes, it meets all my requirements, though I do use it mostly to protect my browser, and use a separate app as a VPN and download-checker (like it checks the things I download for viruses).

good

I work at an I.T. place and it is a weekly occurrence for individuals to bring in their computers claiming they have malware because they got redirected to an adware or malicious webpage.

I've never once encountered such an issue myself. Part of it is just making smart choices online (I.e. Perhaps don't click that random ad... Or go to that sketchy website..) and part of it is using this extension.

10/10 I recommend. Plus it's free!

Works fine for Firefox, does it also work for Google Chrome and the rest of my computer?

J'adore!

When Malwarebytes first came on the scene it was an addon to ones current security great especially for lower quality solutions like what Microsoft provided they also had a pro version (pay once) lifetime updates; great. Over the years as the the industry switched is payment schemes and threats real or imagined became more frequent; Malwarebytes evolved. As a power user I've used lots of free & paid versions security software. I find Malwarebytes is actively improving and I so glad that they haven't wiggled out of their promises they made when they first started. Free software these days is limited; havng a paid version means better support when needed, fully unlocked features, regular updates equaling peace of mind; Malwarebytes Premium is the way to go and with the way it runs. An additional low profile solution running along with it is good too combined with Microsoft's solutions that are useful.... Remember regular backups and the knowledge that a lock is not your safety. It only keeps out the those who are not committed to be where they shouldn't.