It's not that RL Stevenson is a bad ink. It behaves really well on all the papers that I used (notebook filler paper, Rhodia, note pads, comp book paper, etc) It's a smooth ink, but not a wet one. When I tried it in my TWSBI 700 with the original Bock nib it just didn't work very well. It was weak and showed a pale lavender instead of the much more blue hue that I was expecting. That's probably the fault of the nib (I had one of the problematic ones at the time), and so I switched the nib over to one of my Knox nibs and it became much more blue.
That said, if you like the color, then this is an excellent ink. It's just a bit too purple for my tastes. There's really only one purple that I actually like, and that's one from Iroshizuku, so the problem with this ink is really just a matter of taste.
Here's the water drop test I did, and it's not surprising that it doesn't have much in the way of water resistance.