Co-founder of Gustav here. Thanks for the kind words :-) The 3% is of course a blended rate. There are positions/sectors where that would never fly, but others where 5% is feasible. Also we cover the full spectrum of what staffing agencies typically offer, including permanent placement type transactions. For those, our take-rate is closer to 20%.
Here's more info on the pricing: https://hellogustav.com/recruiters-and-staffing-agencies