I bought some "Vishnu" heads a while back, way overpriced, but I took a chance. They looked nice, thick shiny gobs, nice thick gajara but the skins were brittle and the sahayi was prone to chipping. In the end I couldn't use them and I felt like I threw $120. down the sewer. If you're looking at the ones from AACM, or Silverbush in CA, don't. Try sitarsetc.com instead. Aanaddha
Actually, aren't vishnu tablas from bombay? anyhow, i've had some favorable (teachers approval) from Vishal Nagar, feedback on the tablas I bought from www.kalakendar.com. He recommend their Tabla 3, because he knew the maker, and I love them, beautiful rosewood dayan, (and heavy).