They drill very good holes and go through plastic easily, but they also break very easily. I used them to work on a model and ended up breaking 5 of them in a few hours. Although I like it when they come.
Works great. I have used a variety of general purpose HDPE bits. Of course they break easily, they are only .020 inch, they are thinner with grooves. Of course, they must be treated with care.
No matter how strong you think your hand is, you need a Dremel drill to use it. I can hand punch a few holes before breaking a little, but I've made 15 in a row in the press. I think it will seem obvious, but I laid the medallions on a camping stick and figured hand drilling would work. The quick learning curve got me into my abs.