It's watersoluble, it's very dark, it leaves lovely smudges/shadows on your work - you can use a blending stump or water. These were my faces using it and water on Friday
So with the question of alternatives in mind, I decided to do some testing for all of our benefit. When I originally tried to source the Stabilo I went to Office Max. They suggested the Staedtler lumocolor non-permanent (there is also a white which may be useful for sketching on dark backgrounds - purchased but not tested yet). Tried on another page from my altered art journal, but I sprayed first using a stencil with Dylusions ink - also very water-reactive. So this was a fun experiment in itself because the ink remains usable for colour in the eyes etc
Both the above were done with the Staedtler Lumocolor non-permanent pencil (purchased from Office Max) - the page on the left is thicker, but the pencil reacts about the same. Not as dark or as blendable as the Stabilo All 8046 below (same paper as above right) but depends on what you want :
I really like the look of this - nice and dark and a bit more control with using the water with it than the Stabilo. Derwent Graphitint Midnight Black :
Very disappointing - remembering that the graphitint colours are generally more muted than the Inktense, this is still what I would call grey rather than Midnight black! Perhaps if more colour was laid down in the future but I probably won't pursue it since there are some lovely alternatives here. This might be nice for general shadows since not so intense.
Hope that was a useful exercise for you to see as well. Apart from the learning about the pencils, although I didn't spend much time on these faces, the repetition was a useful experience. I'm feeling much more confident about eye position, and I like the nose and lip shapes developing naturally too. In Dina's class, she asked people to do a 'before' face for comparison. I didn't do one since I've been drawing faces since 2015, but often with a lesson for guidance/reminders of proportion. I did find this face from 2016 as a comparison - one I did quickly in my art journal without proper thought to eye position, for example.
Two more things of interest : I haven't tested this with the other pencils but one advantage of the Stabilo All is that if you prepare your surface with gesso first, you can actually remove the pencil marks you don't want completely using a baby wipe - this is VERY useful as you can imagine and should work with the others since they are watersoluble too.
Remember most of these pencils will remain water-reactive so if you're going to continue to work on the art, you'll need to spray with a workable fixative and let that dry before continuing. This is what I currently use -
available at Warehouse Stationery or Office Max. Shop around for specials/best price.
Ask me anything and I'll do my best to help :-)