Did they have the XB1 to PS4 or XB1 / 360 to PS4?
On their site it doesn't list that one.
I got the XBone -> PS4 from CSword so I can test it with the following controllers:
- Horipad
- Xbone official pad
- Mad Catz TE2
I got these converters from Video Games New York when they showed up to for an Anime Conference:
- PS3/PS4 -> Xbone
- X360 -> Xbone
I tested the PS3/PS4 -> Xbone adapter and I can tell you it works properly for the following:
- FC3
- FC4
- DS4
- Hori Real Arcade Pro V
I tested the X360 -> Xbone converter with the stock X360 controller.
I also tested the PS3 -> PS4 converter (at CSword place) with the Qanba Q4 in MKX and Guilty Gear for 2 hours.
Does the PS2 to XB1 converter work perfectly? Would it be allowed at a tournament?
I know CSword tested the PS2 to PS4 and it works fine. I don't have any feedback on PS2 to XB1 since that's a very new converter.
As for tournament legalities, you will need to ask the TO.