After reading for quite a bit here, I have filtered to the following.
1. Feather ( using it )
3. Personna lab blue/med prep / red pack
4. Gillette 7 o'clock yellow/blues/black
5. Astra Superior Platinums ( using it )
6. Treet Durasharp
Of course YMMV ( but recommending Derbys are not true ) but from the list I will try get sample blades to try.