One of the main reason some power users refuse to make the jump from Firefox to Chrome is the lack of proper alternatives to Firefox Extensions. Sure Chrome extension collection has jumped since they started supporting extensions about a year ago and now they have some ~5000 extensions on the Chrome extension gallery but this is no where close to some 58,000 add-ons Firefox currently has. More importantly, because of the intentional limitations in Chrome extension API you cant always have the same type of extension on Chrome like you have on Firefox. It doesnt mean that they will never remove those limitation so that Chrome extensions can be just as powerful as Firefox Add-ons. From my second hand knowledge they are working on extending their API, I cant verify that at the moment.
These limitations of extensions also effect how all the ad-blocker on Chrome work. Chrome ad-blockers dont actually block ads the same way Firefox ad-blockers do. You will be still downloading those ads to your browser but the ad-blockers will just hide the ad elements to remove visual clutter. Its still as good as removing ads like Adblock Plus on Firefox.
This limitation has two implications:
Bad: You are being tracked by ads under chrome with ad-blocker, even if you dont actually see them.
Good: Anti-adblocking scripts dont work on Chrome ad-blockers like they do with Firefox ad-blocker (on Firefox you can still bypass anti-ad-blockers, but needs some custom work).
An interesting observation is that currently Chrome AdBlock Extension is the most popular extension on Chrome extension gallery, it has more than 1 million users and almost more than double the user base of second most downloaded extension, which is Googles own Gmail Mail Checker. Thats 1 out of ~7 chrome users using ad-blockers (Google claims Chrome has 70+ million users). The second most popular Adblock extension is AdThwart which is the 20th most popular Chrome extension with ~200,000 users, as of this writing.
What does it all mean?
I think mostly power users rely on extensions like adblockers, and just like Firefox, early adopters of Chrome are also mostly power users who are helping spread Chrome to the mass.
As mentioned before, both extensions works by hiding ad elements, because of API limitations so they dont actually have any advantage over one another. What we will look at is their implementation of removing ad elements, how they effect the speed of the site and extra options each extensions comes with.
Benchmarking Ad blocking:
We tested 5 popular sites on normal browsing, then using Adblock and finally using Adthwart. Both extensions works under incognito mode (which is how we tested), we made sure that caches were clean before running site with or without each ad-blocker. We were surprised to see that site loaded faster with AdThwart on every single sites we tried on. Admittedly, not by much, but still interesting to see that a less popular ad-blocker has faster site load time than the most popular Chrome ad-blocker.
When it comes to blocking Ads, both extensions blocked (or rather hide) every single ad element on all sites we tried; just like Adblock plus on Firefox.