Did this a couple of weeks back. I know there are always questions on black holos and what could be a good replacement for OPI My Private Jet (original holo version). I think my version of MPJ is the original one. It's pretty holo, if sheer.
Dark holo comparison: three coats each
Index: My Private Jet, sheer charcoal with fairly scattered holo. HTF, right? (I don't really keep track of HTF, non-HTF. I think I got this when the collection first came out and like most of my HTFs, it wasn't hard to find then but it's probably harder to find now....)
Middle: Diamond Cosmetics Chainmail Charm, darker, more greyer, more pigmented charcoal with more tightly packed holo (what I think MPJ should've been like)... for $2.
Ring: Color Club Revvvolution, black holo, similar degree of holo-ness as in Chainmail Charm. Love it! I bought a sort of backup (the Mattese version).
Pinky: China Glaze Let's Do It in 3D, dark silver holo. Packed full of holo goodness.
And now, a video because still photos do no justice to any of these!
Sorry the video's too short... and the sunlight a little too strong. Anyway, out of all of these, MPJ is seems most... glittery and reactive (but not by much), even if it is the most sheer. Hope this helps someone out!
