I will add another answer in for my case. I've changed the break pads (same compatibility resin/organic but the new ones were more expensive than the original). My impression was very negative in the beginning, because the rear brake the new pads stops worse than the old worn brake pads. I went out to test it (burn-in) as the documentation from the shimano says:
- Ride your bicycle in a flat and safe area without obstacles and
accelerate to a moderate speed.
- Operate the brake lever until you slow down to walking speed.
Do this only with one brake lever at a time. Be careful when performing
this procedure. Always operate your brake lever with moderation,
especially when you burn in the front brake.
- Repeat steps 1 and 2 for at least 20 times for both the front and rear
While repeating the process, the brake force will increase.
I did this and it didn't change anything, I went to a competition where there were a lot of descending parts of the trace and there I performed the "Burn-in". After few descendings they feel fine. I do not recommend anyone to do this on descendings, but I've trusted my front brake.