Any Experience with Generational Group (sell or buy side?)

We are not looking to sell, but we have had a number of players in our space tease interest and we do want to be ready when the time and offer are right. We stumbled across a Generational Group event and ended up connecting with them. Their pitch is a flat-fee 5-year retainer to prep and optimize, field interest, and manage a bid process if/when we decide. If we do sell through them then obviously there is a commission component. Anyone willing to share your experience with Generational Group or similar firms? (also happy for any offline feedback)