My two pence worth ... Overall, I'd say the new look forum is a good improvement on the previous version and easier/better to use. I seem to be having some issues though with 'following' topics and with notifications.
In the past version, there was an option to automatically subscribe to the topic/get email notifications when making a reply to a topic. When I have replied to a topic, it looks as if an attempt is made to do this (the bell icon changes from a bell+ icon to bell with tick icon). It appears as if I have been automatically subscribed but when I move to another page and return to the original topic, the icon has returned to a bell+ once again. The topic does not ever automatically appear in the list of followed topics unless I manually tick the bell+ icon to follow.
I haven't received any email notifications of topic updates since the changeover even for topics I am subscribed to.
When I log into the forum, the bell icon in the top RHS of the screen does not show the number of new notifications waiting since I last logged in (although when I click on the bell to view the notifications list, the list does appear to be up to date).
The 'Edit' function is sorely missed. Could this be implemented on a permissions-based approach (maybe granted to users after reaching a certain forum 'rank' with a history of posting)?
Don't seem able to paste in hyperlinks as before, get error message about the HTML being invalid. I need to experiment more with that.
The sticky posts are not missed by me TBH. Many of the previous sticky posts were written a long time ago. If they are reinstated, they could do with a refresh and update IMO to make sure they are up to date and relevant. The way the 'Pinned Discussion' is currently showing on the 'Email' forum as just a single line from the title is a much better use of screen space. The previous way of showing the introductory text from each sticky post, meant scrolling through lots of screen space at the top of each forum each and every visit which was a bit cumbersome.
The 'Security Matters' forum link seems to have gone from the top menu row (though I guess this could be by design if it is not being carried forward in the long term).
Well done to all those concerned with the switchover and having it up and running again 24 hours later!