Disk brakes are good because:
-They can offer more modulation and power than rim brakes.
-They are much better in wet conditions than rim brakes.
-You don't wear out expensive rims.
-They are safer on long mountain descents.
-Rim brakes are good because:
-They are on average 600g lighter than disk brakes.
-They are very simple to set up and adjust.
-It is extremely easy to change the pads, they are cheap and easily available and not very model dependent.
-You don't need to bleed them.
-You don't need to clean out the calipers and clean the pistons.
-They offer a perfectly adequate amount of power and modulation in the dry.
-They don't drag on the rotor.
In short there is no right or wrong answer about whether rim brakes are better than disk brakes. It's about what advantages are more important to you.
True, and obviously we've all survived on rim brakes all these years too, but your rim brake pluses over disc are pretty debatable:
-They are on average 600g lighter than disk brakes.Yes some, but my TCR is roughly 400g heavier than my friends near identical rim brake TCR, that's nothing. And sure, if your hobby is building ultralight bikes or you need to get to the top of hills first because your job is on the line, then maybe that is a serious consideration. But for the vast majority it makes no difference. In fact I've become better and faster at climbing on my disc.
-They are very simple to set up and adjust. Disc brakes are pretty simple too. I always found the trial and error of getting the pads toe'd right so they don't howl, even with gadgets to help, a bit frustrating.
-It is extremely easy to change the pads, they are cheap and easily available and not very model dependent.Changing pads on disc is WAY easier than rim brakes. And swapping between wheels is easier too, don't need to switch or adjust pads/brakes. Pads are about the same price as a good set and cheaper than a good set of pads for carbon wheels. They do wear out a little faster it seems, I am still monitoring this
-You don't need to bleed them. It's been a year and I have not had to bleed mine, and I don't really see any reason why I will need to anytime soon. It's also not that big a deal to do, no worse than trying to thread cable/housing through a frame. My old TCR used to eat cable housings, it was a total PITA
-You don't need to clean out the calipers and clean the pistons.Haven't had to do that either
-They offer a perfectly adequate amount of power and modulation in the dry.Why settle for adequate?
-They don't drag on the rotor.hasn't been a big issue on my disc, it happens occasionally, particularly when they are hot and the rotor expanded and it's annoying because sometimes it makes noise, but goes away in about 20 seconds. Also, the new generation of disc calipers have more spacing. But when I had Sram Red rim brakes on my old bike, I used to have to carry a brake wrench in my kit because it you brushed against the rear brake or bumped it when changing a tire it would go all wonky and rub on the rim. I've met others that had this issue too.
I will tell you the actual issues I've had with disc so far: My brakes started clicking/grinding rather loudly and I could feel it through the levers and it drove me crazy. I was using the ice tech rotors and it seemed the pads were clipping the cutouts along the parameter of the rotor. I went through several sets of pads and rotors trying to fix it to no avail, it would go away and come back, it was frustrating. But no one else seemed to have the problem but me and there are quite a few around here on shimano disc. I found one other person on the internet that had the issue. I ultimately switched to Sram Centerline and the issue went away. Now of course the Sram are not perfect, sometimes after a big braking event, the expansion (as I mentioned above) causes the rotor (which is less robust than the shimano) to touch the pads and they will squeal a little, but it goes away real quick. I've also had the rear rotor make some rubbing noise on a cold damp morning, but that has only happened once so far and I think it may have been because I didn't have the caliper aligned correctly. Again, not a big issue so far
Another issue, is the Shimano R785 rattle on bumps and chip seal if you have your hands on the bar tops, really annoying. I believe this is fixed with the new levers
And there is quite a bit of brake dust, my carbon rim brakes did that too but was easier to clean since there was less nooks and crannies
That's it so far, few minor annoyances but nothing that big a deal.
And since we're talking NorCal mtns. I have Mount Diablo in my backyard and ripping down the mountain with discs is just awesome. And even more importantly they are better for those times when you have to ride the brakes behind a slow car. Much less hand fatigue too.