I like the way discourse handles PMs. You even get the standard 15 minute (used to be five) edit window. Far superior to vBulletin’s email-style PM system and its limited inbox space.
I really, really don’t like that none of the old links to pre-discourse threads and posts work. Particularly links in old threads to other old threads; if they link with a thread ID or a post ID without explicitly telling you the title, you have just no way of knowing what thread it was or how to find it. It’s just gone.
I also really, really don’t like that discourse isn’t compatible with a wide range of BB codes people used to use on the old boards.
Those two negatives combine to make it feel like we just threw out 20 years of history to start over.
But hey, much better PM system, so we’ve got that going for us, which is nice.
EDIT: For context, just the other day I spent the time to recreate a workable table of contents for the SDMB fantasy football dynasty league. Check it out. Each year we create a new thread, link it to the previous thread, maybe the previous thread’s draft results or rules discussion, yada yada yada. At the end of each thread we post a link to the new thread. None of those links work anymore. And many, many posts from previous years (roster lists, draft results, etc…) are very long and now hot garbage because of the formatting issues.