Changing the user IDs gives you a world of trouble. Usually if I delete a member I simply force updates on the relevant logs. SMF is reasonably good at taking care of most aspects of the deletion but things like PM notifications often lag behind.
Yeah, really glad we switched. Pyraxis and I use a forum for communication when we can't IM (like when I was in the hospital). We have accounts the we use kind of like a filing system.
We had phpBB2 because I was too lazy to change it. One day we got 50 spambots registered so I finally bit the bullet and did it.
Aspergers me went through the database deleting the bots and then the numbers were no longer consecutive. Couldn't tolerate that so I "fixed" it without fixing the corresponding posts, which made them orphans. To make matters worse, in a fit of angst I deleted an account that was being useless, except it had been used. The conversion hung up in three places.
For the first two I found a fix for online - just a few changes to the conversion script, and for the deleted account I just switched IDs with an actual unused account.
The conversion script fix changed the orphan post userIDs to "Guest" thereby screwing up the filing system and creating a fourth problem. I had started doing it post by post via the interface, but it took me an hour to fix one account. Since I know nothing about sql and am fearless about breaking my own things, I guessed at the sql code to change the post userIDs back to their proper "owners."
If I had applied the fix to the sql in the first place I would not have had to go through all that. At least I think so, but since everything is working, no way am I going to test it.
The good news is that since it is a private forum and I didn't delete the old one, the only person who had to suffer was me.