Is EventX still an active project? Anyone still use it on newer installations, past 7?
If not, does anyone have good experiences to share regarding integrations with other event or conference systems?
As far as I know it is not an active project anymore. But since it looks like open source you could probably make it work in newer installations of episerver as well. But it is probably still a webforms project and not MVC.
Have no experiences with other system sadly.
BV Network, the Norwegian Episerver branch, have developed a (licensed) plugin for event registration/management called "Attend".
More info here: https://kompetanse.episerver.no/contentassets/8b421ffe1002497e8f5138126f8101c2/attend-sales-sheet.pdf
Don't know if it's been updated in a while, but try contacting them at firstname.lastname@example.org.