Maybe this post should have been entitled "Stopping with the times" :-)
Hydraulic vs cable brakes; disc vs rim brakes
For most of my cycling life I’ve used cable operated rim brakes, either caliper or cantilever brakes, and I’ve generally been satisfied with them.
Nowadays, the cycling industry has decided that bikes should all come with disc brakes. As a consequence, I now have two bikes with SRAM hydraulic disc brakes, and a touring tandem with a Hope hydraulic rear disc brake (with a huge rotor!).
Ease of installation
I’ve only installed one set of hydraulic brakes: a set of Magura hydraulic rim brakes bought on eBay some years ago. With the appropriate tools, cutting, preparing and fitting hydraulic hoses, and filling the system with brake fluid isn’t really much harder than fitting cable actuated rim brakes. I've not installed disc brakes so far, but I don't anticipate that being particularly arduous. Of course, with all kinds of brakes things get a bit more complicated with internally routed cables and hoses. The Magura brakes use mineral oil rather than DOT fluid that my disc brake equipped bikes use.
Ease of service
Our touring tandem is equipped with front and rear V-brakes and a rear hydraulic Hope disc brake. Bleeding that is really a piece of cake, except the caliper is a long way from the lever, which complicates matters if you don't want to disassemble things too much!
One of the SRAM equipped bikes hasn’t needed any brake maintenance so far, but the other has. And it has been a bit of a hassle. This was a winter bike bought as a commuter bike just before the Covid lockdowns meant commuting wasn’t an option. So it hasn’t had a huge amount of use. It has SRAM Rival hydraulic brake / cable gear levers (configured to run a Rohloff hub gear), and by the end of last winter both brakes had become really badly spongy feeling, and when I checked it a couple of weeks ago, I decided they were too bad to be used safely.
Some time back, I’d bought a budget bleed kit for DOT5.1 fluid brake systems, and I set about bleeding these brakes. I watched several YouTube videos on how to bleed SRAM brakes (the best being Park Tool’s video, though it kind of focusses on flat bar levers), and had the instructions that came with the bleed kit.
After a couple of unsuccessful attempts which resulted in the brake performance only improving to barely useable, I bought the rather pricy Park Tool DOT Bleed Kit (BKD-1.2). I also made my own written notes from the Park Tool video to follow.
Tha Park Tool BKD-1.2 bleed kit: rather more to it than a set of cable cutters!
This time, things worked out pretty well. I suspect it was down to the better syringes and tubing in this kit that really helped. The Park Tool syringes are much more comfortable to use, have a smooth action, and the silicone tubing is firmly attached with circlips.
I’ve not had an opportunity to bleed Shimano brakes, but my TT bikes have the Magura hydraulic rim brakes originally devised for TT bikes and which, like Shimano brakes, use mineral oil. These have performed very well and have been easy to bleed when necessary. One set has been in use for over 10 years, the other was bought off eBay and I installed it from scratch.
On the whole it’s fair to say that servicing hydraulic brakes is (or can be) a fair bit more hassle than cable rim brakes.
Are disc brakes significantly better than rim brakes?
The answer to that naive question is definitely “it depends”. The limits to braking are really the traction of the tyre on the tarmac - and safety with the front brake. If you can lock the wheels with both rim brakes and disc brakes, there’s really little difference. For a solo bike with alloy rims, therefore, I don’t really see that disc brakes offer much improvement over rim brakes except maybe in the wet. Wheels with a carbon braking surface generally offer poorer braking than those with alloy rims, and you definitely see superioro braking with disc brakes.
I think assertions that disc brakes prolong longevity of rims are true, but in the last 36 years of cycling I've never worn out a wheel rim.
With our touring tandem, I definitely find braking is better when I have the rear disc brake. In the past (and with the old touring tandem we no longer have), I’ve blown the front tyre off the rim using rim brakes only - so that’s a concern with our summer tandem. It uses only a pair of cantilever rim brakes, and I do need to anticipate when I need to stop.
If I was buying a new bike, I think it would have disc brakes as all decent bikes nowadays are specced with them. I’m happy with that. Would I retire one of my rim brake bikes to replace it with a similar bike but with disc brakes just because of the brakes? No, I wouldn’t, unless some aspect of the bike became difficult to get a replacement - for example aero wheels for a TT bike.