Last week, I bought Bobbi Brown Long-Wear Gel Eyeliner (£15) in the shade "Espresso Ink" which is a black brown colour that is a little less harsh-looking than pure black. I already have a long-wear black gel liner from Smashbox but the black can be a bit much for daytime if used cack-handedly, evoking comments such as "ooh you've done your make-up Egyptian-style today".
"Espresso Ink" definitely looks brown rather than black in the pot, especially next to my Smashbox Jet Set Waterproof Eye Liner in "Midnight Black". But when it's applied, I can barely tell the difference between the two colours. Swatched next to Smashbox "Midnight Black":
However, when I look very closely, "Espresso Ink" looks slightly more watered down and grey, whereas "Midnight Black" is true, black black. Being less stark, "Espresso Ink" does give an overall softer look (especially on the lower lashline), but I was disappointed that it doesn't look dark brown like it does in the pot, but rather a dark grey.
In terms of consistency and application, I prefer Smashbox over Bobbi Brown. The Bobbi Brown gel is too "wet" so the colour doesn't apply evenly, and takes longer to dry. You can see in the swatch photo above that it's washed out down the middle of the stripe, and globby on the edges. The Smashbox gel is more viscous and applies completely evenly, with a truer colour.
I'm still using "Espresso Ink" occasionally, but I'm going to try a browner brown next time... perhaps Smashbox Jet Set Eye Liner in "Dark Brown". I didn't buy this shade before because I read reviews saying that the red tones might not go so well with brown eyes, but I'm now thinking it might be nicer on me than dark grey.
Here's a photo of "Espresso Ink" on my upper and lower lashline (but applied over Yaby Pearl Paint Shadow, so the colour isn't as strong as when worn on bare skin):