There are things I like about both formats. However, some of the features of the old boards I particularly liked, which have already been mentioned - the ability to easily toggle between flat & threaded mode, and being able to see what post a person replied to at a glance. I don't enjoy browsing large threads in threaded mode because it is a pain to keep clicking, I always browsed the old forums in "flat" mode because I could skim through the thread easily and always be able to see to whom each post was in reply. The only thing I used threaded mode for was in giving links in long threads to a specific user's post.
This forum has features that were only available with "Plus" accounts on the other forum such as rotating sigs, and ability to create polls. While the old board poll creation was cumbersome it was pretty flexible. I've only made one poll here by way of test...still not decided which I like better.
I very much like the full blown WYSIWYG post editor option, and even the smilies are cute & reasonably discernable in meaning (hoping there will be an expanded set eventually if this is the board format chosen). I found the smiley set on the old boards to be one of the nicest I have seen on any forum. Some smiley sets are totally lame, bordering on annoying or simply indecipherable in what they are meant to express.
Also our old forum gave users the ability to still appear online to others but keep the area of the forum they were browsing private. I have not seen such a flexible option here - perhaps I simply have overlooked it. The only thing I see is a choice between "invisible" mode or full blown big brother capabilities. Not that it is really a big deal, I just happen to like flexible privacy options.
Overall this seems to be a robust, feature friendly forum. As to the comments on it loading faster...the jury is still out on that, as this is a new forum with only a week's worth of content. When it has a bloated monstrous database with spiraling archives going back years connected to it, then we will see.
I have always been a fan of the muted neutral background colors and understated borders on the Stratics forum and was happy to see it mostly reproduced here. There are some forums that I don't enjoy browsing at all because they are so busy or make my eyes tired with the intense colors and contrasts, etc. While I don't want everything drab and boring, I find the color scheme of this forum to be highly conducive to communication.
-Skylark