I have one bike with Tektro Oryx cantis and the braking is so-so, largely because I put too long of a z-link wire on them... and the pads are a little old. I will be replacing them before my next big ride. The other bike has a set of Avid SD4s with short z-link wires and is a much better stopper. Neither are useless by any means. It is just a matter of configuration.
__________________
--Ben
2006 Trek SU100, 2009 Motobecane Fantom CX, 2011 Motobecane Fantom Cross Uno, and a Bakfiets
Previously: 2000 Trek 4500 (2000-2003), 2003 Novara Randonee (2003-2006), 2003 Giant Rainier (2003-2008), 2005 Xootr Swift (2005-2007), 2007 Nashbar 1x9 (2007-2011), 2011 Windsor Shetland (2011-2014), 2008 Citizen Folder (2015)
Non-Bike hardware: MX Linux / BunsenLabs Linux / Raspbian / Mac OS 10.6 / Android 7