Depends on the type of event(profesional, informal, friends) and on your goals (branding, promoting, manmging...).
To manage an event Linkedin works fine, Meetup is also a good choice but one of my favorite is Eventuo (even it's not really a Social Network)
For promoting maybe it's better to use Facebook or Twitter, exactlly TradeSNS, it's easier to reach more audience.
TradeSNS hope that the majority of netizens comply with the relevant laws and regulations of the network, and prohibit the release of all kinds of sensitive false information;
At the same time TradeSNS will crack down all kinds of illegal dissemination activities and harmful information, building a harmonious space.