Soltype
For what its worth - my Xbox Hori Fighting Commander Octa arrived and I tested it all week on SF6. This is the best 6 face button pad youre going to get on the Xbox at the moment. I think I may even prefer it to the out of print white Fighting Commander from the 360 days.
While ive read mixed opinions online - I, personally, have had no issues with the Dpad from using shotos - to 360 piledriver grapplers - to the precise timings of Dhalsim.
I play as Sim, Lilly, Dee Jay, Guile, Honda - for my character variety for reference.
The best thing about it is the micro switch buttons. These feel good and seem like they will last - a nice click when pressed. For SF6 in particular I put Drive Impact and Drive Parry on 2 of the bumpers.
I like that the Dpad is a bit smaller - less travel needed - charge characters in particular benefit. The Dpad does NOT click like a base Series controller.
The analog is an added benefit for SF6 in particular to move around the 3d hubs and lobbies - much better than using the dpad for that. I would never use the analog to actually play street fighter though.
Minor nitpicks:
The bumpers are a bit strange because they are so large and I sometimes hit one when I dont want to - its more of getting used to the controller I think.
I dont love the placement of the RB and RT buttons because they are on the curve of the outside edge - I wish they were on the flat surface like A B Y X - nothing too major though.
The controller is super light because it doesnt have any rumble nonsense - some people like the light weight others, not.
For a 6 face button pad - this is pretty much your only option on Xbox Series - and it actually is quite good. Its a keeper imo and I wish I got one years ago.
EDIT: I have not tested it on Radiant Silvergun or any shumps yet but it
does seem ideal for those.