The success rate of slow freezing varies depending on the type of tissue being preserved and the specific protocols used. For embryos, survival rates after thawing can range from 60% to 90%. For oocytes, the rates are generally lower, often between 50% and 80%. Ovarian tissue preservation success rates are still being researched, but early results are promising. It's essential to consult with a fertility specialist to understand the specific success rates for your situation.