Hello. I recently downloaded and installed version 7.7 and I have to say I'm quite impressed.
A website that I run was/is currently in ASP and we were using a YaBB forum that was ok, as there wasn't much in the asp forum market at the time.
I finally decided it was time for a change and that I wanted a database backend, instead of the raw text stuff that YaBB does... from this database, I have a few projects that I will want to do with the website with the solid back end, and hopefully implement to increase capabilities.
I had a number of forums to choose from, but this one appealed to me the most at first, and I think I made a very good choice. The forum I run is very small with roughly 20-30 users. I run Windows 2000 Server for the IIS webserver and I simply unzipped all the forum files there and it instantly worked... very impressed there 
Access levels on an individual basis is a huge plus that I needed and I think this forum does it quite well, although I don't like that forum categories are still displayed to users who don't need to see them. It takes up space and is a bit of a security issue for giving unauthorized users to have a hint of a category that aren't suppose to see.
It was a bit intimidating at first with the number of <-- include --> items, but I managed to hack my way through to certain code to find what I wanted. My first step was to get the forum to fit in my web template... was a little painful for a while, but I eventually got it in.
Next was reskinning the forum.. took a little while to figure out that this is done in 2 files. It went pretty well, although my one complaint was the fact my webpage uses white text(thus changing that in the .text category and many others similar to it) by default and there wasn't an individual css entry for the "quick login" text or the big field when you're entering posts (white text in a white box basically). I just added a new class in the css for those and told those items to use that instead, problem solved. I eventually got everything down and was fairly simple... just a lot of experimenting 
Setting up the forum categories and boards was very smooth and I liked the interface for that in the admin area. Excellent work.
I installed... 2 mods I think. One was the calendar mod by aks427 and an avatar mod that grabs subdirectories by EiopManager aka Yair Sappir. Both seemed to work well, although I have a suggestion for the calendar that I will mention in the proper thread
Another modification I tried with success was adding 2 fields to the register.asp page for a more individualized location... I added a "City" field and a "State/Province" field. I simply added 2 fields to the database to the author table where that other info is located and added all the variables that the default "Location" had (changed the name there to "Country"). Wrote to the database just fine... edited the popup profile to include that info, and added some logic to the forum posts that would display what was entered if anything. So I guess the point of that paragraph was I didn't find it difficult to add-on to existing data and forms.
Everything looks good so far and no huge problems that I know of yet. If anybody out there is debating if you should use this forum software, I have to say this a very good product and you won't be disappointed! And best of all, its FREE!
Kudos to the dev team who coded this thing and much support to the modders and general support of the WWF community for continuing to strive and improve this software! 