While it's looking like disc brakes are going to take over in a few years, we're still using Cantilever brakes these days.
Cantilever brakes work okay, but they aren't great. You've got your low-profile brakes such as the Avid Shorty, which are easy to set up but can squeal like a pig. You've got your wide-profile brakes such as the TRP EuroX, which have awesome rim/pad clearance but are a bit underpowered. There's also the problem of fork chatter, where applying the front brake makes the whole bike shake and shudder...not fun.
Enter the v-brake. For mountain bikes, this was the go-to brake type before disc brakes took over. They work great and are very efficient at transferring force into stopping power. However, the road levers we use in cyclocross don't pull enough cable for these brakes to work. Think of it as a leverage thing. A longer lever requires you to move the lever a greater distance. So if you want to use normal v-brakes with road levers, forget about it. Not going to work. But there are workarounds.
You can get a cable adapter (e.g. Travel Agents) to effectively change how much cable your road levers pull, making v-brakes usable. I did this on my single speed. Works great:
If you shorten the arm length of a v-brake, you shorten the lever and therefore don't need to pull as much cable. That's why mini-v brakes can work with road levers.
Mini-V brakes seem to have arm lengths between 8 and 9 centimeters. The shorter the arm, the less power, but the more pad travel. I think pad travel is the most important factor here, because even the above pictured mini-v brake with a travel agent adapter works fine.
TRP makes a sweet mini-v brake targeted for cyclocross usage:
These have 9 centimeter arms, which some SRAM and (I believe) Campy users had trouble with because those road levers don't quite pull enough cable for even minimal pad clearance. So TRP came up with the 8.4, which obviously has 8.4cm arms. That will give more pad/rim clearance, which as I said is most important factor. I don't know why anyone would buy the cx9 (9cm) model when you can get more pad travel from the 8.4s. So if you're going to buy these, get the 8.4s.
Tektro also makes some viable alternatives. They made some TRP knock-offs in the RX6 (9cm arms, do not want), and the RX5 (8.5cm arms, better). Not as cool as the TRPs, but they probably work fine.
What you may not know, however, is that BMX kiddies have been using mini-v brakes for years, and there are some good, cheap brake sets available. After doing a lot of poking around, I found the Tektro 926 has 8cm arms (more pad/rim clearance!). These things were cheap...I think I got the pair for under 30 bucks. I also added a Jagwire adjustable noodle, which is quite handy. The reason I chose these is I wasn't sure if the rim/pad clearance was going to work for me, so this was a cheap gamble. Also, the 8cm arms would give me the most pad clearance I could get with a mini-v brake.
How do they work?
I got a test ride in today with the 926 brakes in Forest Park. Included in the ride was a trip down Fire Lane 5, which is quite demanding of brakes.
The brakes performed well. I could slow down with less hand force than my wide-profile cantis. The pad/rim clearance is okay, at least for dry conditions. I've been able to set the pads up loose, such that I have a little wiggle room should one of my wheels get knocked a little out of true...that stuff happens all the time in cyclocross, so it's stupid to not plan for it.
These brakes exceeded my expectations. I'm pretty pumped. And it's worth noting that I'm using the stock brake pads. I'm sure they're nothing special, so I'm anxious to see how they perform with some Kool Stop Salmon pads. It can only get better.
Minimize Cable Play
If you're going to give these a try, I think the name of the game is minimizing cable play. When you just barely squeeze the levers, you want the pads to barely move. If you have any kinks in your brake cables, replace them. If your cable housing is dirty, replace it. Otherwise, when you squeeze the brake lever, the cable first needs to get tight, then it will start braking. You really don't have any cable pull to spare! These brakes are only going to work well if the system is clean and there is little to no play in the cables.
They work! But that rim/pad clearance could be a deal breaker if your wheels get wobbly or in the mud.