Too bad the aliexpress one breaks. I've had it my cart for a while to try out. The original is over $100 shipped to Canada lol.

Yeah location is definitely key. In Canada prices are crazy for bikes still. A new mechanical 105 carbon TCR with aluminum wheels is 3800cad. Even Canyons and other DTC we have to pay a bunch extra from HST and duty sometimes. The used market is even more crazy than new, decade old carbon 105 rim brake bikes for 1.5kcad is normal. Sometimes you can find good deals for older bikes. But if you want modern carbon frame + carbon wheels there's really no competition here at all if you're comfortable building.

I used this ztto bb: https://www.aliexpress.com/item/33023047002.html?spm=a2g0o.order_list.order_list_main.81.25791802wy98FE

Worked with R7000 105 cranks so it should work with the new ones too? Did take quite a bit of force to get it completely seated.

Those 6 piston calipers are interesting. Very expensive though.

I had an ok time with the Juin Tech F1s. The cable housing/routing seems very important to get them to feel good. Yet another difficulty with integrated handlebars/stem/headset. At least there's some cheaper fully hydraulic groupset options now.

If you have a front derailleur with a cable stop (like 105) you can just dremel out the built in cable guide hole so housing fits through. Much easier to deal with and less fiddly. 

I recently received the new velobuild c ring and it is a big improvement! With the original c ring + microspacers or the kocevelo ring + microspacers I still had a tiny bit of front-back play. Had to push forward on the back of the steerer to notice it. With the new ring there is no more play at all! I still had to use some microspacers with the kocevelo bar combo spacers but maybe with the velobuild bar combo it isn't needed now. The new version is much taller and has a larger opening. Here's an album comparing the original c ring and the new version:
https://imgur.com/a/rupJ6Cd

How is it more annoying? It's the same thing.  Pull the cable, fish a new one.  Or if a housing is needed, pull the old housing an fish a new one. It's no different than other internal routing systems.  I have it on my 2023 Scott and I ran a dropper post housing/cable without disassembly of the headset. Same as internal routing through the frame.  What are people talking about??

How many people here are simply regurgitating what the read on the internet vs actually working with one of these systems first-hand?

One of the most legitimate complaints I've heard is that having the opening on top of the upper bearing may lead to more dirt/water intrusion into the upper bearing. I'll buy into that.

The vb-099 I have is headset routed with internal handlebar/stem routing. Looks cool, no cables hanging out anywhere on the front end. Huge pain to work on using a full mechanical groupset, but at least there's no cables.

Headset routing on a mtb still has cables in front. The cables just go into the headset a few inches up instead of into the frame. Which makes maintenance more annoying. You can't replace your headset bearing without also buying a new olive for your rear brake. Plus disconnecting everything else. Really not that common of a service, but it's still more work for marginal to no gains. Things break on mountain bikes fairly frequently and personally I'd rather not have to deal with more annoying things when fixing stuff. Headset routing for mtbs just doesn't have any positives imo.

That said it'll still probably become more popular like internally routed cables simply because it's cheaper for manufactures.

Guerilla gravity and Deviate have cool solutions for cable routing that make life easier.