Never used the Terramaster, but it appears to be a hardware RAID. OWC doesn't have hardware RAID, they rely upon SoftRAID which really does not play well with Catalina.
SoftRAID seems to work better now (with Catalina). Issue I keep having is every time you run SoftRAID it wants to update the RAID driver again (even though its already up to date) and takes about 60 seconds!
However, once RAID is set up on your drive you rarely have to load up SoftRAID anyways, so its not an issue. I have two ThunderBlade drives and an Express 4m2, and with the RAID set up on them I haven't had to open SoftRAID again. All work perfectly well.
Ive also used Terramaster in the past - another great drive. reliable and very easy to set up and use.
You wont go wrong with either choice to be honest.