Do they design with you, or just deliver a plan you hand over?
The single biggest differentiator. A facilitator who takes your agenda and runs it is a safe pair of hands at best. One who works with you on the design will challenge whether the session can carry what you're asking of it, tell you when three outcomes need to be two, and adjust the format to the group you actually have. Ask them what they'd want to change about your current plan — the answer tells you a lot.

