Now that WD has protected folders I wonder if Avast Free will ever get that feature?
Ransomware Shield - FAQs https://support.avast.com/en-us/article/50/
If all features is in the free then no one will buy premier 
Well, the owners of Avast Free can just uninstall it, to get the feature for free from Microsoft.
Would I swap avast free for Windows Defender from Microsoft, no thanks.
I don’t know exactly what functions are included in its Ransomware option. That is only one function you also have to consider the rest of its protection Vs what you get with avast free. The Behaviour Shield by its nature could also detect ransomware attacks.
One thing that everyone should have (and it has nothing to do with what AV you have) is a robust backup and recovery strategy to be able to recover from a serious problem, not necessarily AV related. I use hard drive imaging software, that creates an exact image of a hard drive/partition, etc. You can do a full backup, incremental backup, preferably to an external hard drive.
I do a weekly full backup and keep the last 6 backup images. If I experience a problem that is likely to take longer than 20-30 minutes, then it is quicker to restore the last backup image. I have done this many times over the years and not one instance has been because of malware, etc.
Based on Reviews I’ve read of the new Microsoft feature nope not gonna try it, Sticking with Avast Free myself for protection, behavior shield should be able to stop ransomware if it detects any, and just make sure have a good backup strategy in place, and keep Windows 10 Up to date, and 3rd party programs, and should be fine
Can you set avast free to check for updates every 120 minutes? Is that the lowest you can set it to?
Why would you do that ?.. avast recive stream updates evry 5-15 minutes