When we were at JD Cycles in Ilkley testing their Ventana, they were telling us about all the brakes they'd tandem tested.
They took two of their heftiest riders to the top of the huuuge road hill out of Ilkley, then came down at warp speed at tried to stop.
They reckoned Magura's were the best overall for power & lack of fade.
Hope V2's not quite as powerful but almost as fade resistant. "They just wouldn't give up" was their comment.
They tried lots of others but wouldn't consider anything else suitable!
They had Maguras on their test Ventana – impressed with power but lever feel bit odd (but then I'm used to Hope's).
Got Hope Ti6's, love 'em. Simple to service (on the odd occasion they do need servicing)and stop us ok, and we're a 28 stone team.
If buying new I'd probably go same as TJ, V2's with vented discs. The heat you can generate is incredible.
Rob