“Best” is a qualitative term any Makerspace could claim as it is subjective to the person making it - so no falsehood.
I just qualify my statement as stating we are the largest by paid membership that I know of in the US. I explain some are bigger but anyone can join and say they are member.
Our membership number reflects people that think there is true value worth paying for. I think that is an objective statement of fact.
At the end of the tour they can decide if they also think we are worth investing their time and money into.