Henson says the Al13 was engineered to work best with Astra SP blades. I get BBS from both the mild and medium Al13. I prefer the mild on the face, medium for head shave. The only difference for me is a bit more blade feel on the medium.I just ordered the Henson Al13 medium, any suggestions for blades or technique? I wasn't sure whether to get the mild or medium as reviews vary so much. I've been pretty happy with a Progress on 3 or 4, would you say the medium is comparable? Thanks, Mark