Samsung Galaxy A20 comparitively better than M20. Its small difference in the price rate.Good quality Camera used in A20.and size 6.4 inches but M20 Size 6.3 inches only, this pieces build in front glass plastic body and Samsung Galaxy A20weight -169g.but Samsung Galaxy M20 Weight-186g.
Technology used in both .GSM/HSPA/LTE.
Under the Os platform Andriod 9.0 used in A20 .Andriod 8.1 used in M20.When ur buying Galaxy A20 you wiil get ear phone along with Samsung Galaxy A20 but not iincluded in Galaxy M20,
I think Samsung Galaxy A20 more better than M20.