Never download anything from any download aggregator websites unless they are explicitly authorized by the software's developer. In the case of PS3 Media Server you have no choice but to use SourceForge, since that is what its developer chose to use. Caution is advised.
Download aggregator websites exist for the sole purpose of collecting clickthrough revenue by delivering targeted advertising to you. They include the two you mentioned as well as countless others. They are notorious for bundling Mac malware with the products they host, most likely without authorization, but that's the developer's problem, not yours. Nearly all of the advertised products are worthless trash that should never be installed on any Mac.