We used liquid chalk markers before they are were pretty bad. So I figured how much worse can these be? Got them yesterday and tested them out immediately. They work fantastic! Took about 10-15 seconds of pushing on it to get the liquid to flow but after that it writes great on my black glass board. Tip is just the perfect width, lines are solid and color is great. The eraser on the cap works pretty good. Not the best if you are trying to erase with it right after you wrote on the board - it just smudges everything and you have to use something else to clean. It does work better after writing stays on the board for a bit - I left mine on overnight and then tried it. The cap eraser did erase it clean but there were flakes left on the eraser that were flying everywhere so I had to clean it over a trashcan. So overall I do like it a lot, I'll just have to use a separate eraser to clean it after.