I have always had a sort of interest in MoM, but the glitchiness, balance issues, and AI problems, even WITH the official patches, sort of turned me off.

Anyway, I've read some patch notes for the unofficial patch (1.40f? Whatever the latest version of it is) and while it does sound like there are a number of AI-related fixes and other improvements, I've never really played the game and as such don't have a baseline for what's fixed and what isn't.

So, yeah, what are your guys' thoughts on said unofficial patch? How much DOES it fix and what areas are still really lacking with it?

There is a nice changelog somewhere on the RealmsBeyond forums where the unofficial fix is hosted.

I think that part of the question is an unspoken, "Is it worth the time and effort?"
So far, I can't say one way or the other, but if the patch is half as good as advertised, then yes, absolutely. (plus the price of "Free" is handy) While I've downloaded and installed the patch, I haven't played around with it yet.
On the other hand, the expanded help files that someone's created ARE well worth it, if sometimes a bit obtuse. They're handy and extremely informative. The obtuse part comes in on what you sometimes have to click to find the next page in the longer help files - asking for help on a "cancel" button seems a little unintuitive!

Keep in touch, though. I've a feeling that the patch is good and worthwhile and fixes a number of annoying little AI habits.