There are definitely advantages to Softraid.... A trade off is that you do have the T2 Caveat that requires you to disable security in order to install the latest SR 5.8.3 (we are working with Apple to eliminate this issue in the near future - at least in terms default driver).
The benefit of softraid is full TRIM enablement which makes a big difference with an SSD blades in array of this performance. Short answer - you will get better RAID 0 performance using Softraid on extended write tasks.
if mainly for read - not going to matter too much.
If want redundancy via RAID 1 - only SR will let you do a 0+1 4 drive array of that kind.. and even if you only mirror sets of 2 drives - SR is nearly twice as fast at reading from a RAID-1 volume (since it striped reads of RAID-1 sets) vs. Apple (which only reads from a single drive in R1). Further - with a RAID-1 set, while Apple OS won't even tell you one of the drives has failed - unless you launch DU and find out there or your 2nd drive fails, you're running without redundancy without warning... Softraid both will warn you when/if a drive has failed + also gives a predictive warning even before failure.
Final bit - you can also do RAID-4 or 5 (RAID 4 actually better with SSDs, RAID 5 better for HD due to performance of drives) which on a 4 blade array gives you both redundancy and the performance benefit over single drives.
SR is included with the Accelsior and it is a good tool - but VERY important you use the latest version. The 5.6.3 driver that ships stock with AppleOS (and usually only allowed 1 update per year, we're working on that) is not ideal with the current 10.15 release. Apple finds bugs, we find bugs - in Apple's bugs or updates or fixes that break prior standards, etc... and need that updated driver). Again, hopefully in the future - by 10.16 - will not need to adjust security or reinstall driver with new OS rev updates too.
Thanks for getting our 4M2 and enjoy that and your new Mac Pro! Some amazing work is being done using those Accelsiors right now for a sequel to a movie that hd ground breaking special effects when it was introduced a good number of years ago. The sequel going to be even more amazing.

and that's jut one thing