There are a lot of fantastic transfers that work well on dark apparel. Some of the problems you may have been reading about probably have to do with ink jet transfers, or transfers made with an ink jet printer for application on darks. Not all ink jet transfer papers are designed to work on darks. I think Stahls has some ink jet papers that work on darks if you want to use your own ink jet printer. Or you can call Transfer Express, they make a lot of different kinds of custom transfers that apply perfectly on dark garments. It all just depends on what you are trying to do, how many you need, etc... hope this helps!
KEB