Both versions are as good as the other but neither is ideal. To such a vague question one person might answer "they were all wearing nice cltothes" and another might say "they listened intently and then asked lots of probing questions and gave the speaker a standing ovation".
To get a better answer you need to be more specific about what you are asking.
Do you want to know what type of peopel came? If so then ask that. Better still, be more specific about what you want to know - what age were the people who went... what height/ age/ sex/ weight/ religion/race etc... or what educational background... scruffy or smart, etc
If you want to ask how they behaved/reacted at the conference you should make that clear.