I'm hoping for more power than the CR720 brakes, with less grabbiness than the Tektro Oryx. (It's surprisingly hard to find a cantilever that will play nicely with STi road levers). One happy coincidence of the geometry of these brakes is more room at the fork crown (the CR720 need the straddle to be down on the mudguard) - hopefully that'll be where my dynamo light goes once my dynohub wheel is built.
First indications are pretty positive - I've run the brakes for a week now, although I've not done a wet ride with them, which is probably the real test they need.
Huge thanks to James at Fine-ADC for getting me these - they're surprisingly hard to lay hands on locally, so I was glad I was able to buy direct from Fine.