Everyone in my coloring groups rave about these pens ... I HATE them. Now, I am sure that they are very nice pens, but they are fundamentally gel pens. If you like gel pens, you'll probably love them. I hate gel pens. I thought these might be better than most because people like them so much. But they are not. The flow is horridly inconsistent, even when you warm them up. The tips constantly clog when you try to layer it (with either alcohol or acrylic markers). And it picks up the colour underneath it instead of just layering over top. I hate all of that. If you decide to use them just for line work (no layering), they still pick up their own ink when you try to fill an area and leave a streaky mess where the ink trenches itself. Just zero proper functionality. Again, not unusual for gel pens, but I expected better from the brand and the reviews.