So after reading other folks' opinions of an Oracle Linux 8 (thanks again, Nicolas!) trial installation, I decided to crank up a Virtual Box session and try an install myself.
As others have stated, what you get when you install OL8 is identical in every way to what you see when installing Centos 8; literally the only difference is the logo and the default desktop background. There are no demands for registration or anything else when you install OL8. It's exactly the same experience as installing Centos 8.
Since I use Mate on my computers (installed from https://copr.fedorainfracloud.org/coprs/stenstorp/MATE/ ) I immediately decided to see if I can get that going.
I ran into two small issues, both easily dealt with.
First, the PowerTools repo doesn't seem to exist under that name on OL8. It's called ol8_codeready_builder, for some reason. "dnf-config-manager --set-enabled ol8_codeready_builder" works fine and gets us where we need to be.
A slightly more serious issue is that the oracle-epel, found through the rpm named oracle-epel-release-el8, appears to be less complete that the original Fedora epel found at https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm. Mate requires ImageMagick as a dependency for caja-image-converter and if you have oracle-epel installed it can't find ImageMagick.
The solution (at least the solution that I used, which worked) is just to delete the oracle-epel-release-el8 rpm and install epel-release-latest-8 rpm instead.
Then the Mate desktop can be installed on OL8 from the copr rpms listed above.
Ultimately, the take-away here seems to be that if you decide to use OL8 instead of Centos 8 you'll be better advised to stick with "real" epel and not the oracle epel since there appears to be at least some stuff missing on the oracle epel.
After I jumped through those minor hoops, what I ended up with was an Oracle Linux 8 installation with a Mate desktop and literally everything looks and works identical to what I already have with Centos 8.
(An issue that I haven't seen anyone address yet is this. It's my understanding that epel builds their stuff on the current RHEL. Therefore the upcoming Centos Stream might get out-of-sync with whatever epel is building on at any given point in time.)