Recommendations for Email Protection

We're potentially in the market for a new email protection and archiving platform that works with O365. Currently we're using Barracuda's Email Gateway Defense and Cloud Archiving Service. It works OK, but we're starting to have more and more issues with it.

I've had a couple of vendors try to sell me on Microsoft's Defender solution, but my experience in the past (about 4 years ago) was pretty bad. One of my biggest complaints about it is that impersonation emails aren't blocked by default, you have to setup a policy with specific users you want to try to block impersonation from. This seems like something that should be blocked globally for any email address in the domain.

What's everyone else using and how happy are you with it? Cost is not the largest driving factor for us, as we're trying to increase security this year to meet some contract requirements (CMMC), but I don't have unlimited budget either.