Shimano cables are great. I don't recommend anything else unless you insist on a firmer brake feel with one of the compressionless varieties out there.
cablemagic is good. I go with SP41 grease myself. I don't buy the "lube will attract dirt" thing.
A- you could say the same about chains
B- where is this dirt going to come from? Won't it come from there without the grease?
C- grease is a decent seal.
D- almost all shift housing is pre-greased. Are these "no lube" people degreasing their shift housing before using it?
E- I'd bet grease w a bit of dirt in it is still smoother for a cable than no lube, and much smoother than dirt w no grease.
chains are different..... you can easily clean a chain ( I do once a week ) cables..... not so much.
teflon cables wear off creating dirt, every time you pull on a cable, be it brake or gear there is a small amount of cable exposed to the elements that gets covered in crap and pulled into the housing.... this is minimalised by sealed cables but not completely. Itmdepends on the climate and conditions the bike is ridden in.
It's just a point of view... no need to take it seriously.... No Rant Here