When comparing avast! vs CleanMyMac X, the Slant community recommends avast! for most people. In the question“What is the best antivirus software for the Mac OS?” avast! is ranked 4th while CleanMyMac X is ranked 5th.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Decent anti-virus protection
Cons
Con Tries too hard to sell you the paid version
Con Too noisy
Avast! has sounds turned on by default. It also has a lot of blinky features of questionable use.
Con Makes your system slower than usual
Even though scans are not being run in background, it will slow your system.
Con Opt-out installation of Google Chrome
These advertising tactics are simply unacceptable.
Con Selling potentially identifying user data
Con Detection rate isn't too solid
Avast! is not the sort of antivirus product to give you peace of mind. In practice, it does miss some malware every now and then. You'll need backup virus protection, which raises the question why you should get Avast in the first place.
Con Expires after a year leaving computer exposed to new viruses
Expires and stops updating after a year after which the user's computer may become infected by new viruses not covered by existing patterns.
Con May interfere with hyper-V
Since avast has its own virtualization engine, it will cause issues with hyper-V.
Con Unable to detect some adware such as FADE adware
Con Blocks or causes issues on apps or games
Con "Smart Screen" feature
When running an unknown application, avast will run it wrapped in a sandbox environment first for scanning, then kill the process and re-run it again. A lot of applications do not like this.
Con Sneaky about trial limitation and prices
Trial version only cleans 500 MB, but it does not disclose that limit before one pushes the button to clean after a scan. While it's OK to provide only limited functionality in a trial version, the appsshould be upfront about what the limitation is.
Especially with an app that is supposed to clean your system, it's really messed up to run an activity only partially, and then ask for money. This is clearly done to play on the insecurities of the less-than-tech-savvy users, who might believe that their machine is now in a worse state than before they ran the app, and need to pay now to get a clean system.
Even when trying to close the nag screen by pressing the little X in the corner, the X turns into "Don't leave yet, get your personal discount", which opens the website and gives you even more discount than their "Deal of the day" which is shown after you download the trial. So people who just go to the website to buy pay $89 (or $69 when they get a deal of the day), but when they pay from the nag screen, they only pay $56. That is not a good way to do business, and even if it were a solid app, it's hard to support these practices.
Con Space Lens reports more storage that the SSD actually provides
For example, a 480GB SSD with 70BG free, and the sum of the folders Space Lens shows in root is about 550GB. That's definitely wrong.
Con Provides no info about things it deletes
The app does not provide any additional information about the files it wants to delete, so the average user cannot make an informed choice what to remove and what to keep. For example, it might prompt you to remove languages other users of your Mac are using. That's not a good idea.
Con Uses just a tiny window for showing details about what the app tries to delete
In full screen view, the part of the screen where the app shows a list of things it wants to remove is about 8% of the screen. So you can see 8 items at a time (out of a list that has about 80 entries), and the name of each of those items is truncated. 75% of a 24"-screen is entirely blank in that view.
Con "Flush DNS Cache" will not boost speed
It will simply flush the DNS cache, so that each request for a web page will require a call to a DNS server first.
Con Claims it will "Free Up RAM"
People who have a clue about memory management will understand that on a Unix system RAM is typically fully used, because that is the way to optimize speed. Any attempt to "Free Up RAM" will lead to other stuff being loaded into RAM immediately: the app might "free" 2 GB of RAM, but if you come back to Safari and look at several tabs, it will soon be back to only 200 MB of free RAM.
Con Expensive
A full license is $89, but there's no way of telling how long you would get free updates. Owners of the previous version will have to pay 50% of that to upgrade. The subscription service is $39 per year. If there's a new major version in the next 3 years, subscription will be cheaper. All that fits with MacPaws being intransparent and sneaky.