There are some problems with Reddit, e.g. the moderation tools are not particularly powerful (e.g. us moderators cannot edit post titles). Discourse is better in this respect, IME (although nothing has happened here that has needed moderator attention yet).
(Both are better than mailing lists.)
I’m slightly concerned about getting overwhelmed in emails from vibrant newbie threads; I believe categories can be muted, but it seems this is a global mute, not just muting emails, which is subpar (i.e. reading the description implies to me that muting a category will disable all notifications, via email and via the website, even if someone explicitly @-mentions you).
This may not be a problem in practice.
Less Wrong uses a modified Reddit codebase.