I prefer the Salix wax on the basis that when I refurb a bat I've just bought (which is always the case) I like to apply a little wax and often after sanding back and in between knocking in sessions. I don't share the comment that wax doesn't soak in as you can feel any excess left on the bat surface. I always leave it horizontal and find it does soak in between 24-48 hours. I try to avoid over-waxing this way too.
It works for me although I do agree that it darkens the willow, which I don't really mind as i always cover with a Hammer Edge Sheet.. personal preferences I guess...