Moving from M to F
I've thought for the last 3+ years of owning my Lamy Safari that I should move to a F nib. I've been lazy about it, but finally broke down and did it recently. I wish I'd done this a long time ago!
A Lamy M nib is a generally wet writer, and so is a F, but the line it produces is fine enough that when using a wetter ink I don't have as much feathering and bleed-through on the crummy paper we use at work. (Yes, I break down I buy my own Rhodia notebooks for work, but I refuse to use them just for scratch paper--most of the time.) I would say this nib is equal to its M counterpart in smoothness. It required absolutely no adjusting and in true Lamy fashion slipped easily and securely into place.
I have nothing at all bad to say about this nib. I love it!