Ironically, if this forum were vBulletin, I’d advise the complete opposite. vBulletin, phpbb3, Invision and SMF all follow the same design pattern that hasn’t changed in 10+ years.
Discourse blows these out of the water as it’s designed for 2014+, and not the year 2000. You can login with anything and discussions run in a similar way to what people are used to with FB/Twitter, which makes bringing in new users easier.
I’m not going to go into a side-by-side comparison, but I’d definitely never use propietary software like vBulletin, which costs hundreds of dollars when Discourse presents a superior alternative that is free and open source. Plus it’s made by the same people who started StackExchange.
Yeah, if you’re coming from traditional forums it might take some getting used to. For example, you can unpin topics as a user by clicking on the pin icon. This only affects your view of the forum, but is very handy as otherwise you’d be stuck seeing the same pinned topics six months down the line.