When comparing avast! vs Microsoft Security Essentials, the Slant community recommends Microsoft Security Essentials for most people. In the question“What are the best free anti-viruses for Windows?” Microsoft Security Essentials is ranked 4th while avast! is ranked 7th. The most important reason people chose Microsoft Security Essentials is:
MSE doesn't seem too resource intensive
Ranked in these QuestionsQuestion Ranking
Pros
Pro Decent anti-virus protection
Pro Performance
MSE doesn't seem too resource intensive
Pro Simple and Silent
Does the job without distracting you.
Pro Less prone to false positives compared to other solutions
Frequent false positives in themselves can reduce security
Pro Ease of Use
Pro Accuracy
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 Used as non-competitive baseline since 2013
All except one tested antivirus scores above Security Essentials.