Observations, some of which are anecdotal, some of which are not
* As Fallow notes, Discord has a first-class supported client on Macs and mobile devices. This is "nice".
* I personally think that the chat component is very nice, in that a) it's great for ephemeral shit-shooting (that doesn't translate well to the forums) and b) allows for a rich text/media experience and c) is stupid easy/simple to use from mobile platforms (which - IMO - is absolutely not true for the forums)
* TRR tends to not use the chat function excessively (cat photos at the request of Kristin, notwithstanding), however another guild that I'm in uses it very heavily. I think its a nice thing to have, honestly.
* 4/5 TRR raiders feel that Discord's voice quality is superior (significantly so) than Vent's. That 5th raider may be dead - we're sending out a search party now.