As far as who the lines are designed for, theyre similar. Theyre designed to be stiffer, looser fitting pads. However, from what i felt when i checked pads out in pure goalie,
Stiff- 2s pro, s29
Flexible- Ef4, Optik (both chassis), P2, GT, Gnetik IV
not stiff, but not soft (medium)- G4, SLR1/2, V8
Honestly, i added the s29 bc it was extremely stiff for a mid level pad. i know they have an nxg core but theyre still VERY stiff for a mid price point pad. MUCH stiffer than its competitors like the P2.9, G4 Senior, Slr pro (not pro carbon), etc
Maybe i use a lot of force when flexing my pads, but i didnt find too many pads in the store to be that crazy stiff, i could flex a lot of them pretty easily.