From examining the drivers, the manufacturer(s) would be in the same order as you listed 😉
1. BTC
2. BTC
3. BTC
The drivers all contain the file BTCCDRW.SYS
As I have stated to another member, BTC are not very reliable drives. Furthermore, I believe that both Hi-Val and Digital Research are actually owned by I\O Magic. Rebates from any of these companies usually require a telephone call before they are willing to pay.