[@chrishajer Participant 16 years, 2 months ago]

Yes, it will work fine with many users. It’s in use at WordPress.org if you want to see lots of users and activity. https://wordpress.org/support/

You can also check the top 100 sites using bbPress here and see how they feel to you:

http://bbshowcase.org/forums/view/top100

You can find forums with lots of users, lots of posts, or both.