This ink and I have been together since the beginning. I love it for its amazing ability to stay put when doing a watercolor wash over the top. You will need to be comfortable doing your lines in your sketch in a dark blurple... and that just isn't for everyone.
I went looking for something a little more neutral. It took me a long time to find a black that works just as well (deAtramentis Document Ink Black). I don't feel like Noodler's Ink offers a black that doesn't smudge or run a little when wet. Noodler's 54th Massachusetts is the closest to black that meets this criteria. Some folks think that Lexington Gray is waterproof enough. I disagree.
Working on these fish, I actually started with ink on wet. After the fish were all dry, I went in with watercolor and all the Kung Te-cheng ink stayed put beautifully.
Noodler's Ink comes in at an amazing price point and I love that Nathan Tardif is a small batch quirky sort of fellow. I almost have a full dozen of his ink bottles. Kung Te-cheng and many others have great archival and bulletproof properties as well. Bulletproof in the case of his ink means that it is forgery proof. So this is some serious ink.
It is an ink that likes to be used in a pen. Aside from when it's in my TWSBI Eco, I need to use it daily otherwise it can be a bit hard to get it going. I've never had it ruin a pen, but I hear it is one that is harder to clean out.