I have mixed feelings about Edelstein a s a line. The inks aren't bad. But they're not as good as the price tag would suggest. On the other hand Pelikan does a great job communicating with pen enthusiasts and engaging them in activities (Pelikan Hub, creating the color of the ink of the year).
My feelings change nothing - each year I'm eager to try their new ink. I've played for a while with Aquamarine and I'd like to share my view. I didn't expect to enjoy the color and while I'm not crazy about it, I must say it's quite interesting, especially in braoader nibs. The ink is fairly waterproof and offers nice and smooth flow - at least in pens I've fillied with it. I haven't observed any bleedthrough or feathering. I'm not sure if I'll keep the bottle or if I'll resell it, but this ink is really good.
PS: Be sure to check excellent Namreshnoom review.
Drops of ink on kitchen towel
Tomoe River, Kaweco Sport Classic, B
Leuchtturm 1917, Kaweco Sport Classic, B
Poljet, Graf von Faber-Castell Tamitio, B
Oxford, Graf von Faber-Castell Tamitio, B