@Keren16 I think both MT and 7RP are excellent quality. The MT B30 insert is a fair bit longer than the 7RP B30 insert. Because I carry my B30 cinched about 1/2 closed, I find the MT presses the sides of my bag out. Thus, I prefer the 7RP for my B30.
For someone who does not cinch their bag but leaves it loose, both inserts probably work equally well. On days I want my bag completely closed, I use the Fourbi 20, which does not touch the sides at all in my B30.
Funny enough I actually love the MTB30 insert for my B35!
My 7RP K32 insert is for a retourne.