I haven't explored much in the way of varying graphite in a while, yet spent a lot of money experimenting and have determined, at least among Pentel: I really dig their Graphgear 1000 metallic mechanical pencils; relative to their other plastic things; it has a tactile feel with some nice knurling that pleases my fingers.
I've observed some other mechanical pencils which have fascinating mechanisms to I guess rotate the graphite to facilitate more even wear? I have not gone down that rabbit hole yet. So many choices, so little financial wherewithall.
Nonetheless, thanks for sharing your finds! In particular, I have been desiring a better eraser; I'll give that Staedler-Mars a go!
CC:
@tom jennings