Bought a white one of these a while back. I used it quite frequently and I have to say I love it. This thing literally writes on anything. I once wrote on an oily rusted piece of metal and it worked perfectly. Its kinda annoying picking the scab off each time but for the price you cant go wrong.
I bought a red one of these babies and holy sh*t was I impressed! It writes so smoothly and is very weather resistant. These are far better than the sakura paint stick. Stop thinking about it and buy one of these markers! you won't regret it.