I've tried 3 lots of cantis with Tiagra levers, on a Surly Long Haul Trucker. Bear in mind that cantilever power is HUGELY dependent on geometry, so its worth playing with this a little, having keyed in the values for your frame;
http://www.circleacycles.com/cantilevers/
Your results could well be pretty different to the ones I get.
That said:
Tektro Oryx
For: Cheap, Best power, high-ish straddle, narrowest profile of all three brakes
Against: Grabbby, very quick pad wear (meaning frequent adjustments to the brakes required), squeal if not toed in, impossible to get inflated tyre past brake, or unhook straddle, pads must be set v close to rim
Tektro CR-720
For: Cheap, Easy set up, slowest pad wear and least frequent adjustment of all the brakes I tried. Straddle can be unhooked, inflated tyre will go past the pads.
Against: Least power of all three, straddle must be set as low as possible (a problem if you want to mount light to the fork crown, for example), very wide
IRD CAFAM
For: Power somewhere between Oryx & CR-720, not grabby, pad wear quick, but manageable
Against: Most expensive of the three I tried, Hard to find (although Fine ADC will sell to you direct), straddle can't be unhooked, pads must be set pretty close to the rim to be effective (not as close as Oryxes though).
Mini Vs are worth a look too - this thread on Road Bike review has some pretty comprehensive info for pairing them up with road levers.
http://forums.roadbikereview.com/cyclocross/my-mini-v-setup-146309.html
(I've not tried Mini Vs, btw).
Oh, also, good pads will make a massive difference.
Tektro brakes come with middling, hard compound pads, bin them and get Fibrax X-Treme, Kool Stop Salmon, or Yokozuna pink. The IRD brakes come with really good pads (Yokozuna pink).
Bin link wires (Oryx & IRD come with those) and use an adjustable straddle instead. The CR-720 comes with an EXCELLENT straddle hanger, and you can get those as an aftermarket part;
http://www.zepnat.com/component/page,shop.product_details/flypage,shop.f...
A fork crown mounted hanger is, ime, better than a spacer mounted hanger too - reduces judder and squeal in the brake.