MJCs should be good quality, but only used if you have a burner which has it in the firmware or has SolidBurn.
There is no per se quality problem, only a support problem.
This is similar to early CMC and MBI discs.
After some more googling I found out that MJC is somehow related to JVC. NEC ND-4550A, ND-3550A, BenQ DW1640 BSHB, LG GSA-4163B A105, Nu-tech DDW-164 17QF, MSI DR16-F v130 know MJC ME too (which, however, does not mean that they burn it well).
Support for MJC ME has been added to LG GSA-4163B with A103, so that's pretty old news actually.
Matth: Are the MJC discs Advanced Azo? Do they have the ZD... stamper code?