Powder coat is thick enough to prevent correct chain engagement. If you want black chainrings which are going to look like crap due to the colour wearing off the teeth, anodise. If you want something that looks like it was supposed to be black with silver teeth, get something which has the teeth machined after the blank has been coloured, e.g. Thorn, Gebhardt, TA etc.
Powder coat is thick enough to prevent correct chain engagement. If you want black chainrings which are going to look like crap due to the colour wearing off the teeth, anodise. If you want something that looks like it was supposed to be black with silver teeth, get something which has the teeth machined after the blank has been coloured, e.g. Thorn, Gebhardt, TA etc.