Had Hope mini, Old BB7, new BB7, Mono trial and gusset disc...along with some maggie setups.
Best for power was the magura ( cousts light sharp grind ) so much bite was lovely up to front.... next was the avid, (\although i have snapped 3 calipers all old style ) pretty close to the magura just with masses of spoke flex as to be expected on a stock. The mono trials was next best but not as much hold or bite as the BB7 for me .
Brand new I'd go avid, second hand hope all the way..so much better value for your money.