Cantis have got a lot better in the last few years. Too late to head off the advance of disc brakes, but great for those of us who still need them.
On my main ultra-racing bike which has done maybe 25k km, I have had four sets.
I first had Tektro mini-Vs. They worked well but needed to be readjusted too frequently so were a pain.
After a couple of years, I swapped them for Tektro CR710 cantis. These were absolutely excellent brakes, better than the calipers on my audax bike. The front squealed horribly, even though I tried to toe it in, but it was worth it for the performance (plus useful for warning people I was there / braking - but horrible for group riding, and made me use the back brake much more than I otherwise would have).
Last year I bought some carbon wheels for this bike and set up some old wheels with fat tyres to use off road. I needed to use short road brake shoes for the carbon blocks and wantedbrakes that would open completely to allow me to easily change wheels, esp with the fat tyres. The Tektros didn't have enough clearance from the fork to open fully, so I changed again, this time to Avid Shorty 4. These have the fork clearance I wanted. They are not quite as good as the Tektros for braking but not far off. One thing I did change was they have a noodle arrangement rather than a straddle wire, but you can chuck that away and fit a generic straddle wire, which is easier to use and allows me to get them to open as I want them to (there is a safety reason for the noodle thing, but I am aware of and accept the risks).
I also got some Avid Shorty Ultimates (which have a proper straddle cable) but I took them out of the box and they looked a bit wierd to fit - they don't have the normal spike to go into the canti boss, but seem to rely on friction. There were no instructions in the box, and googling was only partially helpful so I decided I CBA to do the research and stuck with the modified Shorty 4s.