I am myself very inexperienced rider - i m riding a unique 100 (with front disc brake) and I feel TONS of difference between this bike and my big B's GS150 (only drum brakes) in terms of BRAKING
Disc Brake is a BOON - NEMAT hai ye bhai سبحانه و تعالى اللّٰه ki - there is no comparison between drum and disc i can assure you that from my experience
However, I have two minor accidents, FRONT disc brakes played some role in those. But the real cause of both of those accidents was WRONG USE OF DISC BRAKE. See myself being very inexperienced, my reflexes caused me to turn the handle while braking hard (both rear and front disc brake).
But you seriously cant turn the handle bar HARD at decent speed (40+) and BRAKE hard front in the same time, cause this will cause the bike to SQUEEZE in itself while change direction too. I feel the SQUEEZE happens because you are completely denying and STOPPING the power which is still coming from the rear tyre (Since rear is a disc brake and its WHERE the power is applied, not easy to stop it specially with drums)
And then this HARD change in direction (WHILE BRAKING HARD) MULTIPLIES the SQUEEZE all causing the bike to jerk and fall down.
This happened with me both the times. I was so worried I thought all the local mechanics are right, this disc brake is a KILLER (lol). I then asked Big B whos is actually a much much shareef cautious striaght line no overtaking rider
He said nothing like that happened to him ever. Even when he had to brake hard at speeds over 90 (He DO play with throttle in low traffic )
Talking to him made me realize you just cant brake HARD the front and turn HARD in the same time, rather , you have to maneuver the bike (handle the bike by laying hard LEFT or RIGHT) and BRAKE both front and rear and try to avoid the collision (or whatever reason you are BRAKING for) RATHER THAN JUST STOPPING THE BIKE COMPLETELY IN VERY LITTLE TIME)
so actually its all about handling, the lessons I learned were:
1.) Brake as early as possible and be ready for BRAKE situations - because even a 70cc accelerates very quick, playing with the throttle can bring BRAKE situation every now and then
2.) Use BOTH BRAKES simultaneously, when required HARD or even in Normal conditions, using BOTH brakes minimizes the SQUEEZE that occurs in using FRONT disc only
3.) When using both brakes (IN HARD BRAKING SITUATIONS), try to alternate the front with the disc and mix it (brake front, then rear, then both, brake and release both brakes in their terms, don't just keep BRAKING all the way since that will lead you to screeches and BIKE dis balance from the rear side). If very hard braking required, of course your reflexes wont allow you to alternate as you will press every thing available lol.
4.) Maneuver the BIKE ( unless in very heavy traffic ot someone overtaking and very near to you) when braking hard rather than keep direction straight towards the collision point. Remember your objective (when braking hard) is to avoid collision (unless your destiny has arrived and you have to park the bike lol) and not to stop