I have a bunch of canti's in boxes and bags that i have used. 2 bikes worth of Frogglegs in blue and black, a set of M900 with an extra front pair, M650's, and a set of Avid Shorty Ultimate and i can honestly say that they were all about the same as each other. All used with the same BXP pads , Paul Moon Unit hangers, and 9 speed Campag Ergo or Sram Rival 2nd gen style drop bar levers.
Frogglegs the lightest and with TRP Inplace adjustable pad holders you can dial in the toe , without bending anything. Great for mud clearance, but the brass bushings wear and get sloppy on the posts really quickly and the nuts are made of cheese so use the right spanner and don't let the threads seize. I used cable adjusters ,that fitted into the arms ,with mine. Not sure what brake they were supposed to be used with.
M900's worked as brakes and that is about it. The only problem i had was the thread for the grub screw ,that you use for centralising the arms , was not to full depth. This meant i could not balance them properly and it did my head in until i realised the grub screw was not allowed to go ,what was probably only 1mm more, into the arm. Bad batch, or common issue and not realised?. Sorted that with a tap but can't remember the thread size.
M650's worked as brakes and that is about it. They are cheap and work.
Avid Shorty Ultimates are well made, and look good, but I am glad i didn't pay anywhere near full price for them. They work well, but they are absolutely not some great advancement in canti brake performance. I used them in both positions and stuck with the position that doesn't catch pedestrians, as you cycle past.
If you use them; make sure you tap out the barrel, that has the wee grub screw, that pinches the straddle cable and grease the thread. The grub screw can seize fast in the barrel , very easily, and the provided screws are made of cheese. Replacing these grub screws with better quality screws is a good move, too. Worth doing because replacement barrels are not cheap.
Also; a mod for the rear is to do away with the straddle adjuster barrel and replace it with another pinch barrel. I did this because i managed to kick the adjuster out of its barrel when dismounting, which seems easier to do than you would think. I noticed this is a mod that cyclocrossers were doing so it is a thing , and not just me and clumsy feet.
The stupidly thin o-rings, that are on the barrels, are very prone to snapping, vanishing, degrading etc so bear that in mind too.
If a gun was put to my head and i was asked to choose i think i would choose the Campag levers with the Frogglegs, or the Sram levers with the 650's as they were the two set ups that made me say, "ooh!....my brakes work well". I got the M900's working really well at one point, but i struggled to find the magic setup after a dis-assembly. I think the way forward would be making a jig , once the setup is spot on, you could use for repeatability. Something more accurate than eyeballing angles anyway.
What i learnt from all of the playing about with angles and straddle heights was lever flex and ratio, post position, cable routing and quality, cable stops and hanger all play big roles in performance and what works for one, may not work for another if you change any of the parameters.
Sometimes, as with the very first time i used the Campag levers and Frogglegs, you can casually slap it all together and you wonder what all the fuss was about. Other times it can always remain frustratingly close to brilliant no matter how hard you try.
Then it rains and you wonder why you bothered.
