Welcome to the forum and enjoy exploring. In terms of MIG compared to other anti-malware solutions, you should be aware of a fundamental difference between them. Pretty much every AV solution employs a "black list" approach. Basically, they use heuristics and definition files to identify and block "known malicious" applications, but they otherwise default to allowing activity. That keeps them from being so obtrusive that users are driven to disable them, but it also means they can fail to block certain malware. MIG takes the opposite and much more hard-line approach, called a "white list". It operates on the premise that Macrium's applications are trusted, and everything else is categorically not trusted. That obviously makes it less flexible, which is why the white list design is typically considered impractical for solutions that are designed to protect multiple file types that might need to be edited by multiple applications. But in the case of MIG, it's only focused on protecting backup files, and those typically only need to be modified by Macrium applications, so it can "afford" to use this design -- and as a result it is both simpler and more secure than the other solutions' black list-based designs can ever be.
Additionally, I remember a thread a while ago where someone found that running a full system scan with some Norton product caused MIG alerts to pop up about blocking unauthorized access. Macrium replied that MIG is basically working as designed there, because for reasons that are unclear, Norton during its scan tries to open those files for write access, which MIG is meant to block. So if you want to use MIG, you should exclude the folder that contains your backups from scans. You should also be aware that third-party anti-virus in general has occasionally been found to block or dramatically slow down certain Reflect operations, particularly backups and Rescue Media creation, so keep an eye out for that. If you have those issues, you may need to exclude the applications in the Reflect installation folder from scanning. I gave up on third-party AV when Microsoft introduced Security (which was later rolled into Windows Defender), and especially in this era of frequent Windows releases, I've found that it's simply a poor cost/benefit proposition. Third-party solutions don't seem to fare notably better than Windows Defender in independent tests these days, and especially in this era of frequent Windows 10 releases, AV solutions can and have created problems such as BSoDs after updates more frequently because they hook the OS in ways that Microsoft doesn't support. And then there are the cases where third-party AV itself has become a security vulnerability. Turns out that when your application embeds itself deeply into the OS and inserts itself basically everywhere, a flaw in your code that can be exploited by an attacker gives them pervasive access to your system. Norton was in the news for this not long ago. So my philosophy has been that if I'm not getting noticeably better protection, it doesn't make sense to accept the interference with legitimate activity and increased risk of stability and security issues, and in many cases pay a subscription for the privilege.
Macrium has a KB article about anti-virus and some other utilities here
if you're interested.