I have no experience with a combined braking system (although there are or have been many motorcycles that came with this..I think of Honda more than others)
My biggest concern with combined brakes would be low speed, parking lot braking. You do not want to grab front brake during a slow speed maneuver. Curious if linked brakes do anything to overcome this?
That is just one issue with linked or CBS braking systems. However, they aren't all the same. Some do have features to prevent low speed maneuver issues. For example, Harley's system will only link if you apply the brakes at more than 25 MPH. If you do they will stay linked until you release them. If you apply them at less than 25 MPH they won't link. Talk about confusing. Lets say you apply the brakes right around 25MPH. Did they link or not?
On the Piaggio BV350 the you have to apply at least 70% braking force before it links. So in low speed light braking it won't link. Again, what exactly is 70%.
Many systems are linked all the time. Apply the rear brake and you get some front.
Some, like BMW link the rear brake to the front brake lever.
Some are completely linked. Apply either brake and get both.
My Like has a CBS pump that decides how much to send to each brake.
??
So I have almost no idea what it's doing. At least I also have ABS so if I overuse one of the brakes the ABS will save my butt. I have tried applying just the rear brake on gravel. If I apply it fairly hard the rear wheel will start cycling the ABS while the front just rolls so it is biased to the rear. How much? Who knows. Its a stupid system but overall the dual discs with Bosch ABS works very well.
When I brake on slippery surface I use more rear brake and less front than on clean dry pavement. With linked or CBS brakes you really don't know how much of each brake you are using.