Whichever burning speed I chose in brasero it wrote the media at the maximum available burning speed. Hence the underlying (?) wodim writing speed options were at least not correctly set. For example, I cannot burn either CDs at 4x-8x speeds or single-layer DVDs at 4x speed.
Edit: I just installed Brasero 3.4.1 on my Debian and at last it seems to work again, even with checksums. There is no wodim requirement (if ever this was the case) in this version either. But still no way to choose lower writing speed than max.
brasero 3.4.1 still corrupts at least DVD+RW where xfburn works flawlessly
I tried with two non-blank working DVD+RW, burning an ISO image on the first one and a common bunch of directories/files on the other one => now ureadable supports and I guess that all will be ok after erasing and burning again the same data with xfburn.
Edit3: xfburn wins ! At least for me, brasero is definitely broken.