I'm not sure the moderators will allow me to post any specifics. I'll say this much: Viking apparently is no longer in business, reportedly because of legal problems. They used to have a Web site at cat69.com (no longer there). After reading some allegations about Viking on a now-defunct Nevada board similar to MERB, I contacted someone who had been a client there. His story was very different from the official story that Viking was putting out: that the girls were "models" from Europe, all were tested for STDs and the club was all-inclusive, legal and safe. After doing some research I came to the conclusion that those claims were dubious at best.
I know that there are presently at least two or three of these type of clubs in the DR. I don't know who owns them but the fact that they are in the DR and not in Costa Rica or some other location where there is any regulation leads me to think that it's a caveat emptor situation.